Particles of recycled polycarbonate resin and method for producing same

Abstract

Provided are: particles of a recycled polycarbonate resin which are characterized by having an oligomer content of 1.4% or less and a molecular weight distribution (Mw / Mn) of 2.3 or less, both determined by gel permeation chromatography (GPC); or particles of a recycled polycarbonate resin which are characterized by having an oligomer content of 0.8% or less and a molecular weight distribution (Mw / Mn) of 2.3 or less, both determined by gel permeation chromatography (GPC), and having a specific surface area of 0.05-1.2 g / cm3 as determined by a gas adsorption method. The particles of a recycled polycarbonate resin have a feature of having excellent impact resistance, heat resistance (hue after molding), and transparency.

Description

Recycled polycarbonate resin particles and manufacturing method thereof

[0001] The present invention relates to recycled polycarbonate resin particles. More specifically, the present invention relates to recycled polycarbonate resin particles having a low content of low molecular weight components and a specific molecular weight distribution, and a method for producing the same. The present invention also relates to recycled polycarbonate resin particles having a low content of low molecular weight components and a specific molecular weight distribution and specific surface area, and a method for producing the same.

[0002] Plastic materials are used in a wide range of applications, taking advantage of their characteristics such as impact resistance, light weight, and processability. In most current industrial manufacturing methods, plastic materials are not produced as a single molecular weight substance, but as a mixture with a molecular weight distribution. Low-molecular-weight components degrade the physical properties of plastic materials, so their content is desirable to be low. Furthermore, various additives are added to plastic materials to improve weather resistance, flame retardancy, and design. However, these additives and their modified products often contain low-molecular-weight components, which can impair physical properties, so the amount added must be appropriately controlled.

[0003] In recent years, in response to resource depletion and growing environmental awareness, recycling, in which plastic materials are recovered and remolded for reuse, has become increasingly common. Recovered plastic materials contain a large amount of low-molecular-weight substances compared to virgin resins due to the deterioration (decomposition) of the resin during their manufacturing (molding) and use processes, and because various additives are added to them. Therefore, there is a strong need to remove these low-molecular-weight substances.

[0004] In addition, recycled plastic materials have the disadvantage that it is difficult to specify the desired physical and chemical properties and achieve the desired color because waste plastics with various colors are mixed, processed, and refined. Therefore, it is desirable to remove colorants as much as possible to make it easier to adjust the color tone.

[0005] Conventionally, methods for extracting and removing low molecular weight substances by contacting a plastic material with an organic solvent that does not dissolve the plastic material have been known, and for example, Patent Document 1 discusses the appropriate low molecular weight component ratio and size of polycarbonate resin particles. However, Patent Document 1 relates to virgin materials, and the appropriate low molecular weight component ratio and molecular weight distribution of polycarbonate resin particles differ for recycled materials that have different amounts and types of low molecular weight substances, and there has been almost no discussion of the low molecular weight component ratio and particle size of recycled materials, or methods for achieving them.

[0006] Japanese Patent Application Publication No. 4-306227

[0007] An object of the present invention is to provide recycled polycarbonate resin particles that are excellent in impact resistance, heat resistance (color after molding) and transparency, and to provide a method for efficiently producing the recycled polycarbonate resin particles.

[0008] As a result of extensive research, the present inventors have found that by using recycled polycarbonate resin particles that have a low content of low molecular weight components and a specific molecular weight distribution, or recycled polycarbonate resin particles that have a specific molecular weight distribution and specific surface area, it is possible to provide a recycled material that is excellent in impact resistance, heat resistance (color after molding) and transparency, and have completed the present invention.

[0009] That is, according to the present invention, the object of the invention is achieved by the following: 1. Recycled polycarbonate resin particles characterized by having an oligomer content of 1.4% or less as determined by gel permeation chromatography (GPC) and a molecular weight distribution (Mw / Mn) of 2.3 or less. 2. Recycled polycarbonate resin particles as described in the above item 1, in which the total amount of benzotriazole-based ultraviolet absorbers having a molecular weight of 1,000 or less is 1,000 ppm or less. 3. Recycled polycarbonate resin particles as described in the above item 1 or 2, in which the number of foreign matter insoluble in methylene chloride collected with a nylon mesh having an opening of 20 μm is 1,500 or less per 50 g of recycled polycarbonate resin particles. 4. Recycled polycarbonate resin particles having an average major axis of 200 to 5,000 μm and a solubility parameter of 16 to 30 MPa. ０．５ 4. A method for producing recycled polycarbonate resin particles according to any one of items 1 to 3 above, characterized in that the recycled polycarbonate resin particles are contacted with an organic solvent of the formula (I) for 10 minutes to 7 hours. 5. A method for producing recycled polycarbonate resin particles, comprising dissolving the recycled polycarbonate resin particles obtained by the method for producing according to item 4 above in a halogenated hydrocarbon solvent, filtering the recycled polycarbonate resin solution, and then removing the halogenated hydrocarbon solvent to produce recycled polycarbonate resin particles. 6. A method for producing recycled polycarbonate resin particles, comprising dissolving the recycled polycarbonate resin particles obtained by the method for producing according to item 4 above in a halogenated hydrocarbon solvent, and before and / or after filtering the recycled polycarbonate resin solution, subjecting the polycarbonate resin solution to one or more of water washing, acid washing, and alkali washing, and then removing the halogenated hydrocarbon solvent to produce recycled polycarbonate resin particles. 7. The oligomer content determined by gel permeation chromatography (GPC) is 0.8% or less, the molecular weight distribution (Mw / Mn) is 2.3 or less, and the specific surface area measured by gas adsorption is 0.05 to 1.2 g / cm ３8. Recycled polycarbonate resin particles according to the above item 7, in which the total amount of benzotriazole-based ultraviolet absorbers having a molecular weight of 1,000 or less is 500 ppm or less. 9. Recycled polycarbonate resin particles according to the above item 7 or 8, in which the number of foreign matter insoluble in methylene chloride collected with a nylon mesh having an opening of 20 μm is 500 or less per 50 g of recycled polycarbonate resin particles. 10. Recycled polycarbonate resin particles according to the above item 7 or 8, in which the number of foreign matter insoluble in methylene chloride collected with a nylon mesh having an opening of 20 μm is 500 or less per 50 g of recycled polycarbonate resin particles. 11. Recycled polycarbonate resin particles obtained by dissolving a recycled polycarbonate resin in a halogenated hydrocarbon solvent, filtering the recycled polycarbonate resin solution, removing the halogenated hydrocarbon solvent, and then filtering the polycarbonate resin solution to obtain a polycarbonate resin having a specific surface area of ​​0.06 to 1.5 g / cm as measured by a gas adsorption method. ３ The recycled polycarbonate resin powder is produced, and the resulting recycled polycarbonate resin powder and a solubility parameter of 16 to 30 MPa are mixed. ０．５ 11. The method for producing recycled polycarbonate resin particles according to any one of items 7 to 9, wherein the polycarbonate resin solution is subjected to one or more of water washing, acid washing, and alkali washing before and / or after filtering the recycled polycarbonate resin solution.

[0010] The recycled polycarbonate resin particles of the present invention, which have a low content of low-molecular-weight components and a specific molecular weight distribution or a specific molecular weight distribution and specific surface area, are a recycled material that is excellent in impact resistance, heat resistance (color after molding) and transparency and can be widely used as a material for various molded products, and therefore have extremely significant industrial effects.

[0011] The present invention will be described in detail below. <Recycled Polycarbonate Resin (Raw Material)> The recycled polycarbonate resin (raw material) that can be used in the present invention refers to an injection-molded product containing polycarbonate resin, or crushed sprue or runner generated during injection molding, an extrusion-molded product such as a film or sheet, or crushed scrap generated during extrusion molding, and pellets made from these crushed products in an extruder. Any of post-consumer recycled (PCR) material, post-industrial recycled (PIR) material, and recycled materials consisting of a combination thereof may be used.

[0012] In this case, the method for recovering the recycled polycarbonate resin (raw material) is not particularly limited. In general, flakes obtained by removing (separating) different resins and other materials other than resins from recovered products collected by specialized businesses such as scrap collectors and recyclers, crushing, washing, and drying them, or pelletizing them using an extruder or the like can be used.

[0013] <Polycarbonate Resin> The polycarbonate resin in the recycled polycarbonate resin (raw material) used in the present invention is preferably one obtained by reacting a dihydric phenol with a carbonate precursor. Examples of the reaction method include interfacial polymerization, melt transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds.

[0014] Representative examples of the dihydric phenol used herein include hydroquinone, resorcinol, 4,4'-biphenol, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl)pentane, 4,4'-(p-phenylene) Examples of suitable dihydric phenols include 4,4'-(m-phenylenediisopropylidene)diphenol, 4,4'-(m-phenylenediisopropylidene)diphenol, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ester, bis(4-hydroxy-3-methylphenyl)sulfide, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene. Preferred dihydric phenols are bis(4-hydroxyphenyl)alkanes, and among these, bisphenol A is particularly preferred and widely used in terms of impact resistance.

[0015] In the present invention, in addition to bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, it is also possible to use special polycarbonate resins produced using other dihydric phenols. For example, polycarbonate resins (homopolymers or copolymers) using 4,4'-(m-phenylenediisopropylidene)diphenol (hereinafter sometimes abbreviated as "BPM"), 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "Bis-TMC"), 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter sometimes abbreviated as "BCF") as part or all of the dihydric phenol component are suitable for applications where dimensional change due to water absorption and dimensional stability are particularly strict requirements. These dihydric phenols other than BPA are preferably used in an amount of 5 mol % or more, and particularly 10 mol % or more, of the total dihydric phenol components constituting the polycarbonate resin. In particular, when high rigidity and better hydrolysis resistance are required, the following copolymer polycarbonate resins (1) to (3) are particularly preferred: (1) A copolymer polycarbonate resin in which, based on 100 mol % of the dihydric phenol components constituting the polycarbonate resin, BPM accounts for 20 to 80 mol % (more preferably 40 to 75 mol %, and even more preferably 45 to 65 mol %) and BCF accounts for 20 to 80 mol % (more preferably 25 to 60 mol %, and even more preferably 35 to 55 mol %). (2) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol components constituting the polycarbonate resin, BPA accounts for 10 to 95 mol% (more preferably 50 to 90 mol%, even more preferably 60 to 85 mol%) and BCF accounts for 5 to 90 mol% (more preferably 10 to 50 mol%, even more preferably 15 to 40 mol%). (3) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol components constituting the polycarbonate resin, BPM accounts for 20 to 80 mol% (more preferably 40 to 75 mol%, even more preferably 45 to 65 mol%) and Bis-TMC accounts for 20 to 80 mol% (more preferably 25 to 60 mol%, even more preferably 35 to 55 mol%).

[0016] These special polycarbonate resins may be used alone or in a suitable mixture of two or more. They may also be used in a mixture with a commonly used bisphenol A polycarbonate resin. The production methods and properties of these special polycarbonate resins are described in detail in, for example, JP-A Nos. 6-172508, 8-27370, 2001-55435, and 2002-117580.

[0017] Among the various polycarbonate resins mentioned above, those having a water absorption rate and a glass transition temperature (Tg) within the following ranges by adjusting the copolymerization composition, etc., are particularly suitable in fields where dimensional stability is required, since the polymer itself has good hydrolysis resistance and exhibits significantly reduced warpage after molding: (i) a polycarbonate resin having a water absorption rate of 0.05 to 0.15%, preferably 0.06 to 0.13%, and a Tg of 120 to 180°C, or (ii) a polycarbonate resin having a Tg of 160 to 250°C, preferably 170 to 230°C, and a water absorption rate of 0.10 to 0.30%, preferably 0.13 to 0.30%, more preferably 0.14 to 0.27%.

[0018] Here, the water absorption of a polycarbonate resin is a value measured using a disk-shaped test piece having a diameter of 45 mm and a thickness of 3.0 mm, after immersion in water at 23°C for 24 hours in accordance with ISO 62-1980. Furthermore, Tg (glass transition temperature) is a value determined by differential scanning calorimetry (DSC) measurement in accordance with JIS K7121. Carbonyl halides, carbonate diesters, haloformates, etc. are used as carbonate precursors, and specific examples include phosgene, diphenyl carbonate, and dihaloformates of dihydric phenols.

[0019] When producing a polycarbonate resin from the dihydric phenol and carbonate precursor by interfacial polymerization, a catalyst, a terminal stopper, an antioxidant to prevent oxidation of the dihydric phenol, etc. may be used as needed. The polycarbonate resin of the present invention also includes branched polycarbonate resins copolymerized with a trifunctional or higher polyfunctional aromatic compound, polyester carbonate resins copolymerized with an aromatic or aliphatic (including alicyclic) bifunctional carboxylic acid, copolymerized polycarbonate resins copolymerized with a bifunctional alcohol (including alicyclic), and polyester carbonate resins copolymerized with such bifunctional carboxylic acid and bifunctional alcohol. The resulting polycarbonate resins may also be a mixture of two or more of the resulting polycarbonate resins.

[0020] The branched polycarbonate resin can impart anti-drip properties to the thermoplastic resin composition of the present invention. Examples of the tri- or higher functional aromatic compound used in such a branched polycarbonate resin include phloroglucin, phloroglucside, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, 4-[4-[1,1-bis(4- Examples of the 4-hydroxyphenyl ether include trisphenols such as {4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol, tetra(4-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)ketone, 1,4-bis(4,4-dihydroxytriphenylmethyl)benzene, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, and acid chlorides thereof. Among these, 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, and 1,1,1-tris(4-hydroxyphenyl)ethane is particularly preferred.

[0021] In the branched polycarbonate resin, the structural units derived from a polyfunctional aromatic compound preferably account for 0.01 to 2.5 mol%, more preferably 0.05 to 1.5 mol%, and even more preferably 0.05 to 1.0 mol%, of the total 100 mol% of the structural units derived from a dihydric phenol and the structural units derived from such a polyfunctional aromatic compound. Furthermore, particularly in the case of the melt transesterification method, branched structural units may be generated as a side reaction, and the amount of such branched structural units is also preferably 0.001 to 2.5 mol%, more preferably 0.005 to 1.5 mol%, and even more preferably 0.01 to 1.0 mol%, of the total 100 mol% of the structural units derived from the dihydric phenol. The proportion of such branched structures can be calculated by 1H-NMR measurement.

[0022] The aliphatic difunctional carboxylic acid is preferably an α,ω-dicarboxylic acid. Preferred examples of the aliphatic difunctional carboxylic acid include linear saturated aliphatic dicarboxylic acids such as sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, and icosane diacid, as well as alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. The difunctional alcohol is more preferably an alicyclic diol, such as cyclohexanedimethanol, cyclohexanediol, and tricyclodecanedimethanol.

[0023] The reaction modes for producing the polycarbonate resin of the present invention, such as interfacial polymerization, melt transesterification, carbonate prepolymer solid-phase transesterification, and ring-opening polymerization of cyclic carbonate compounds, are well known in various literature and patent publications. The viscosity-average molecular weight of the polycarbonate resin used in the present invention is preferably 12,500 to 32,000, more preferably 16,000 to 28,000, and even more preferably 18,000 to 26,000. Polycarbonate resins with a viscosity-average molecular weight of less than 12,500 may not exhibit good mechanical properties. On the other hand, resin compositions obtained from polycarbonate resins with a viscosity-average molecular weight of more than 32,000 may exhibit poor moldability.

[0024] The viscosity average molecular weight in the present invention is determined by first calculating the specific viscosity (η ＳＰ ) was measured using an Ostwald viscometer from a solution of 0.7 g of polycarbonate dissolved in 100 ml of methylene chloride at 20°C, and the specific viscosity (η ＳＰ ) = (t - t ０ ) / t ０ [t ０ is the number of seconds for methylene chloride to fall, and t is the number of seconds for the sample solution to fall]. ＳＰ ) and calculate the viscosity average molecular weight M using the following formula: ＳＰ / c = [η] + 0.45 × [η] ２ c (where [η] is the intrinsic viscosity) [η] = 1.23 × 10 －４ M ０．８３ c=0.7

[0025] The viscosity average molecular weight of the polycarbonate resin in the thermoplastic resin composition of the present invention is calculated as follows: The composition is mixed with 20 to 30 times the weight of methylene chloride to dissolve the soluble components in the composition. The soluble components are collected by filtration through Celite. The solvent in the resulting solution is then removed. The solid obtained after solvent removal is thoroughly dried to obtain a solid of components soluble in methylene chloride. 0.7 g of this solid is dissolved in 100 ml of methylene chloride, and the specific viscosity at 20°C is determined in the same manner as above. The viscosity average molecular weight M is then calculated from the specific viscosity in the same manner as above.

[0026] The polycarbonate resin of the present invention may be a polycarbonate-polydiorganosiloxane copolymer resin, which is preferably prepared by copolymerizing a dihydric phenol represented by the following general formula (1) with a hydroxyaryl-terminated polydiorganosiloxane represented by the following general formula (3):

[0027]

[0028] [In the above general formula (1), R １ and R ２each independently represents a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxy group; when there are a plurality of each, they may be the same or different; e and f each represent an integer of 1 to 4; and W is a single bond or at least one group selected from the group consisting of groups represented by the following general formula (2):

[0029]

[0030] [In the above general formula (2), R １１ , R １２ , R １３ , R １４ , R １５ , R １６ , R １７ and R １８ each independently represents a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms; R １９ and R ２０ each independently represents a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxy group; when there are a plurality of groups, they may be the same or different; g is an integer from 1 to 10, and h is an integer from 4 to 7.]

[0031]

[0032] [In the above general formula (3), R ３ , R ４ , R５ , R ６ , R ７ and R ８ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and R ９ and R １０ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, p is a natural number, q is 0 or a natural number, and p+q is a natural number from 10 to 300. X is a divalent aliphatic group having 2 to 8 carbon atoms.

[0033] Examples of the dihydric phenol (I) represented by the general formula (1) include 4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxy-3,3'-biphenyl)propane, 2,2- Bis(4-hydroxy-3-isopropylphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)propane, 4,4'-dihydroxyphenyl)diphenylmethane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-sulfonyldiphenol, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 2,2'- Dimethyl-4,4'-sulfonyldiphenol, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 2,2'-diphenyl-4,4'-sulfonyldiphenol, 4,4'-dihydroxy-3,3'-diphenyldiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-diphenyldiphenyl sulfide, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,Examples include 4-bis(4-hydroxyphenyl)cyclohexane, 1,3-bis(4-hydroxyphenyl)cyclohexane, 4,8-bis(4-hydroxyphenyl)tricyclo[5.2.1.02,6]decane, 4,4'-(1,3-adamantanediyl)diphenol, and 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane.

[0034] Among these, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4'-sulfonyldiphenol, 2,2'-dimethyl-4,4'-sulfonyldiphenol, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, and 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene are preferred, and 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane (BPZ), 4,4'-sulfonyldiphenol, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene are particularly preferred. Among these, 2,2-bis(4-hydroxyphenyl)propane is the most suitable due to its excellent strength and durability. These may be used alone or in combination of two or more.

[0035] As the hydroxyaryl-terminated polydiorganosiloxane represented by the above general formula (3), for example, the compounds shown below are preferably used.

[0036]

[0037] Hydroxyaryl-terminated polydiorganosiloxane (II) can be easily produced by subjecting a phenol having an olefinically unsaturated carbon-carbon bond, preferably vinylphenol, 2-allylphenol, isopropenylphenol, or 2-methoxy-4-allylphenol, to a hydrosilylation reaction at the end of a polysiloxane chain having a predetermined degree of polymerization. Among these, (2-allylphenol)-terminated polydiorganosiloxane and (2-methoxy-4-allylphenol)-terminated polydiorganosiloxane are preferred, with (2-allylphenol)-terminated polydimethylsiloxane and (2-methoxy-4-allylphenol)-terminated polydimethylsiloxane being particularly preferred. The hydroxyaryl-terminated polydiorganosiloxane (II) preferably has a molecular weight distribution (Mw / Mn) of 3 or less. In order to achieve even better low outgassing properties during high-temperature molding and low-temperature impact resistance, the molecular weight distribution (Mw / Mn) is more preferably 2.5 or less, even more preferably 2.3 or less, and particularly preferably 2 or less. If the molecular weight distribution exceeds the upper limit of this preferred range, the amount of outgassing during high-temperature molding may be large, and low-temperature impact resistance may be poor.

[0038] Furthermore, in order to achieve a high level of impact resistance, the diorganosiloxane degree of polymerization (p+q) of the hydroxyaryl-terminated polydiorganosiloxane (II) is suitably 10 to 300. The diorganosiloxane degree of polymerization (p+q) is preferably 10 to 200, more preferably 12 to 150, and even more preferably 14 to 100. Below the lower limit of this preferred range, the impact resistance that is a characteristic of polycarbonate-polydiorganosiloxane copolymers is not effectively exhibited, while above the upper limit of this preferred range, poor appearance appears.

[0039] The polydiorganosiloxane content of the polycarbonate-polydiorganosiloxane copolymer resin usable in the present invention is preferably 0.1 to 50 wt % based on the total weight. The polydiorganosiloxane component content is more preferably 0.5 to 30 wt %, and even more preferably 1 to 20 wt %. At or above the lower limit of this preferred range, excellent impact resistance and flame retardancy are achieved, while at or below the upper limit of this preferred range, a stable appearance that is less susceptible to the effects of molding conditions is likely to be achieved. The polydiorganosiloxane polymerization degree and polydiorganosiloxane content can be calculated by 1H-NMR measurement.

[0040] In the present invention, the hydroxyaryl-terminated polydiorganosiloxane (II) may be used alone or in combination of two or more. Furthermore, other comonomers than the dihydric phenol (I) and the hydroxyaryl-terminated polydiorganosiloxane (II) may be used in an amount of up to 10% by weight based on the total weight of the copolymer, provided that the use of these comonomers does not interfere with the performance of the present invention.

[0041] In the present invention, a mixed solution containing an oligomer having a terminal chloroformate group is prepared in advance by reacting a dihydric phenol (I) with a carbonate ester-forming compound in a mixed solution of a water-insoluble organic solvent and an aqueous alkali solution. When producing the oligomer of dihydric phenol (I), the entire amount of dihydric phenol (I) used in the method of the present invention may be converted into the oligomer at once, or a portion of the oligomer may be added as a post-added monomer as a reaction raw material to the interfacial polycondensation reaction in the subsequent stage. The post-added monomer is added to rapidly proceed with the polycondensation reaction in the subsequent stage, and does not need to be added if not required.

[0042] The method of this oligomer formation reaction is not particularly limited, but is usually preferably carried out in a solvent in the presence of an acid binder. The proportion of the carbonate-forming compound used may be appropriately adjusted taking into account the stoichiometric ratio (equivalents) of the reaction. When a gaseous carbonate-forming compound such as phosgene is used, it is preferably blown into the reaction system.

[0043] Examples of the acid binder include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases such as pyridine, and mixtures thereof. Similarly, the proportion of the acid binder used may be determined appropriately in consideration of the stoichiometric ratio (equivalents) of the reaction. Specifically, it is preferable to use 2 equivalents or a slight excess of the acid binder relative to the number of moles of the dihydric phenol (I) used to form the oligomer (usually 1 mole corresponds to 2 equivalents).

[0044] The solvent may be any of various solvents inert to reactions, such as those used in the production of known polycarbonates, and may be used alone or in combination. Typical examples include hydrocarbon solvents such as xylene, and halogenated hydrocarbon solvents such as methylene chloride and chlorobenzene. Halogenated hydrocarbon solvents such as methylene chloride are particularly preferred.

[0045] The reaction pressure for oligomer formation is not particularly limited and may be atmospheric, elevated, or reduced pressure, but it is usually advantageous to carry out the reaction under atmospheric pressure. The reaction temperature is selected from the range of -20 to 50°C, and since heat is often generated during polymerization, water or ice cooling is desirable. The reaction time depends on other conditions and cannot be specified in general, but is usually carried out for 0.2 to 10 hours. The pH range for the oligomer formation reaction is similar to that of known interfacial reaction conditions, and the pH is always adjusted to 10 or higher.

[0046] After obtaining a mixed solution containing an oligomer of dihydric phenol (I) having terminal chloroformate groups in this manner, the mixed solution is stirred while adding the hydroxyaryl-terminated polydiorganosiloxane (II) represented by general formula (3), which has been highly purified to a molecular weight distribution (Mw / Mn) of 3 or less, to the dihydric phenol (I), and the hydroxyaryl-terminated polydiorganosiloxane (II) and the oligomer are subjected to interfacial polycondensation to obtain a polycarbonate-polydiorganosiloxane copolymer.

[0047]

[0048] (In the above general formula (3), R３ , R ４ , R ５ , R ６ , R ７ and R ８ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and R ９ and R １０ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, p is a natural number, q is 0 or a natural number, and p+q is a natural number from 10 to 300, and X is a divalent aliphatic group having 2 to 8 carbon atoms.

[0049] When carrying out the interfacial polycondensation reaction, an acid binder may be added as appropriate, taking into account the stoichiometric ratio (equivalent) of the reaction. Examples of acid binders include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases such as pyridine, and mixtures thereof. Specifically, when the hydroxyaryl-terminated polydiorganosiloxane (II) or a portion of the dihydric phenol (I) used is added as a post-added monomer to this reaction stage, it is preferable to use 2 equivalents or more of alkali relative to the total moles of the post-added dihydric phenol (I) and hydroxyaryl-terminated polydiorganosiloxane (II) (usually 1 mole corresponds to 2 equivalents). Polycondensation by interfacial polycondensation reaction between an oligomer of dihydric phenol (I) and the hydroxyaryl-terminated polydiorganosiloxane (II) is carried out by vigorously stirring the mixture.

[0050] In such a polymerization reaction, a terminal terminator or a molecular weight modifier is usually used. Examples of the terminal terminator include compounds having a monovalent phenolic hydroxyl group, such as ordinary phenol, p-tert-butylphenol, p-cumylphenol, tribromophenol, etc., as well as long-chain alkylphenols, aliphatic carboxylic acid chlorides, aliphatic carboxylic acids, hydroxybenzoic acid alkyl esters, hydroxyphenyl alkyl acid esters, and alkyl ether phenols. The amount used is in the range of 100 to 0.5 mol, preferably 50 to 2 mol, per 100 mol of the total dihydric phenol compounds used. Naturally, two or more compounds can be used in combination.

[0051] To promote the polycondensation reaction, a catalyst such as a tertiary amine (e.g., triethylamine) or a quaternary ammonium salt may be added. The reaction time for such a polymerization reaction is preferably 30 minutes or more, more preferably 50 minutes or more. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfide may be added.

[0052] A branching agent can be used in combination with the above-mentioned dihydric phenol compound to produce a branched polycarbonate-polydiorganosiloxane. Examples of trifunctional or higher polyfunctional aromatic compounds used in such branched polycarbonate-polydiorganosiloxane copolymer resins include phloroglucin, phloroglucside, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, 4-[4-[1 ,1-bis(4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol, trisphenols such as tetra(4-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)ketone, 1,4-bis(4,4-dihydroxytriphenylmethyl)benzene, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, and acid chlorides thereof. Among these, 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, and 1,1,1-tris(4-hydroxyphenyl)ethane is particularly preferred. The proportion of the polyfunctional compound in the branched polycarbonate-polydiorganosiloxane copolymer resin is preferably 0.001 to 1 mol %, more preferably 0.005 to 0.9 mol %, even more preferably 0.01 to 0.8 mol %, and particularly preferably 0.05 to 0.4 mol %, based on the total amount of the polycarbonate-polydiorganosiloxane copolymer resin. １ It can be calculated by H-NMR measurement.

[0053] The reaction pressure can be reduced, normal, or increased, but is usually preferably normal pressure or the natural pressure of the reaction system. The reaction temperature is selected from the range of -20 to 50°C, and in many cases, water or ice cooling is desirable because heat is generated during polymerization. The reaction time cannot be generally specified because it varies depending on other conditions such as the reaction temperature, but is usually 0.5 to 10 hours.

[0054] Optionally, the obtained polycarbonate-polydiorganosiloxane copolymer resin may be subjected to appropriate physical treatment (mixing, fractionation, etc.) and / or chemical treatment (polymer reaction, crosslinking treatment, partial decomposition treatment, etc.) to obtain a desired reduced viscosity [η ＳＰ The resulting reaction product (crude product) can be subjected to various post-treatments such as known separation and purification methods to recover a polycarbonate-polydiorganosiloxane copolymer resin of the desired purity (degree of purification).

[0055] The average size of the polydiorganosiloxane domains in the polycarbonate-polydiorganosiloxane copolymer resin molded article is preferably in the range of 1 to 40 nm. Such an average size is more preferably 1 to 30 nm, and even more preferably 5 to 25 nm. Below the lower limit of this preferred range, impact resistance and flame retardancy may not be sufficiently exhibited, while above the upper limit of this preferred range, impact resistance may not be stably exhibited.

[0056] The average domain size and normalized dispersion of the polydiorganosiloxane domains in the polycarbonate-polydiorganosiloxane copolymer resin molded articles of the present invention were evaluated by small angle X-ray scattering (SAXS). Small angle X-ray scattering is a method for measuring diffuse scattering and diffraction that occur in the small angle region of scattering angles (2θ) less than 10°. In this small angle X-ray scattering method, if a substance contains regions with different electron densities of approximately 1 to 100 nm in size, the diffuse scattering of X-rays is measured based on the electron density difference. The particle size of the object to be measured is determined based on the scattering angle and scattering intensity. In the case of polycarbonate-polydiorganosiloxane copolymer resins that form an aggregate structure in which polydiorganosiloxane domains are dispersed within a polycarbonate polymer matrix, the difference in electron density between the polycarbonate matrix and the polydiorganosiloxane domains causes diffuse scattering of X-rays. The scattering intensity I at each scattering angle (2θ) within a range of scattering angles (2θ) less than 10° is measured to obtain a small-angle X-ray scattering profile. Assuming that the polydiorganosiloxane domains are spherical and that there is variation in particle size distribution, a simulation is performed using commercially available analytical software based on a hypothetical particle size and hypothetical particle size distribution model to determine the average size and particle size distribution (normalized variance) of the polydiorganosiloxane domains. Small-angle X-ray scattering allows for accurate, simple, and reproducible measurement of the average size and particle size distribution of polydiorganosiloxane domains dispersed within a polycarbonate polymer matrix, which cannot be accurately measured by observation with a transmission electron microscope. The average domain size refers to the number average of the individual domain sizes. The normalized variance refers to a parameter obtained by normalizing the spread of particle size distribution by the average size. Specifically, it is the value obtained by normalizing the variance of polydiorganosiloxane domain sizes by the average domain size, and is expressed by the following formula (1):

[0057] In the above formula (1), δ is the standard deviation of the polydiorganosiloxane domain size, and Dav is the average domain size.

[0058] <Components other than polycarbonate resin in recycled polycarbonate resin (raw material)> In the present invention, the recycled polycarbonate resin (raw material) may contain, as components other than polycarbonate resin, a recycled polycarbonate resin (raw material) containing known functional agents such as a mold release agent, a heat stabilizer, an ultraviolet absorber, a flow modifier, and an antistatic agent. The main additives that are thought to be contained in these recycled polycarbonate resins (raw material) used as raw materials include the following:

[0059] (i) Mold Release Agent: The recycled polycarbonate resin (raw material) used in the present invention may also contain a mold release agent, provided that the effects of the present invention are not impaired. Examples of mold release agents include fatty acid esters, polyolefin waxes (such as polyethylene waxes and 1-alkene polymers, and those modified with functional group-containing compounds, such as acid-modified ones, can also be used), fluorine compounds (such as fluorine oils typified by polyfluoroalkyl ethers), paraffin wax, and beeswax. Among these, fatty acid esters are preferred in terms of ease of availability, mold releasability, and transparency. The mold release agent may be contained in an amount of preferably 0.005 to 0.5 parts by weight, more preferably 0.007 to 0.4 parts by weight, and even more preferably 0.01 to 0.3 parts by weight per 100 parts by weight of the recycled polycarbonate resin (raw material). When the content is above the lower limit of the above range, the effect of improving the mold releasability of the polycarbonate resin is clearly exhibited, while when the content is below the upper limit, adverse effects such as mold contamination during molding of the polycarbonate resin are reduced.

[0060] Among the above, fatty acid esters, which are preferred as release agents, will be described in more detail. Such fatty acid esters are esters of aliphatic alcohols and aliphatic carboxylic acids. Such aliphatic alcohols may be monohydric alcohols or polyhydric alcohols (dihydric or higher). The number of carbon atoms in the alcohol is preferably in the range of 3 to 32, more preferably 5 to 30. Examples of such monohydric alcohols include dodecanol, tetradecanol, hexadecanol, octadecanol, eicosanol, tetracosanol, ceryl alcohol, and triacontanol. Examples of such polyhydric alcohols include pentaerythritol, dipentaerythritol, tripentaerythritol, polyglycerols (triglycerol to hexaglycerol), ditrimethylolpropane, xylitol, sorbitol, and mannitol. Polyhydric alcohols are more preferably used in fatty acid esters.

[0061] On the other hand, the aliphatic carboxylic acid preferably has 3 to 32 carbon atoms, and aliphatic carboxylic acids having 10 to 22 carbon atoms are particularly preferred. Examples of such aliphatic carboxylic acids include saturated aliphatic carboxylic acids such as decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid, octadecanoic acid (stearic acid), nonadecanoic acid, icosanoic acid, and docosanoic acid (behenic acid), as well as unsaturated aliphatic carboxylic acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, eicosenoic acid, eicosapentaenoic acid, and cetoleic acid. Among the above, aliphatic carboxylic acids having 14 to 20 carbon atoms are preferably used. Saturated aliphatic carboxylic acids are particularly preferred. Such aliphatic carboxylic acids are typically produced from natural fats and oils, such as animal fats (beef tallow, lard, etc.) and vegetable fats (palm oil, etc.), and therefore these aliphatic carboxylic acids are typically mixtures containing other carboxylic acid components with different numbers of carbon atoms. Therefore, aliphatic carboxylic acids are also produced from such natural fats and oils, and are in the form of mixtures containing other carboxylic acid components. Fatty acid esters with an acid value of 20 or less (which can be essentially 0) are preferably used. However, in the case of full esters, it is preferable to contain at least a small amount of free fatty acid to improve mold releasability. In this regard, full esters with an acid value in the range of 3 to 15 are preferably used. Furthermore, fatty acid esters with an iodine value of 10 or less (which can be essentially 0) are preferably used. These properties can be determined by the method specified in JIS K 0070.

[0062] The aforementioned fatty acid esters may be either partial esters or full esters, but partial esters are preferred in terms of better release properties and durability, with glycerin monoesters being particularly preferred. Glycerin monoesters are primarily composed of monoesters of glycerin and fatty acids. Suitable fatty acids include saturated fatty acids such as stearic acid, palmitic acid, behenic acid, arachic acid, montanic acid, and lauric acid, and unsaturated fatty acids such as oleic acid, linoleic acid, and sorbic acid. Glycerin monoesters primarily composed of glycerin monoesters of stearic acid, behenic acid, and palmitic acid are particularly preferred. These fatty acids are synthesized from natural fatty acids and, as mentioned above, form mixtures. Even in such cases, fatty acid esters containing glycerin monoesters at a ratio of 60% by weight or more are preferably used.

[0063] In addition, partial esters are often inferior to full esters in terms of thermal stability. In order to improve the thermal stability of such partial esters, partial esters with a sodium metal content of preferably less than 20 ppm, more preferably less than 5 ppm, and even more preferably less than 1 ppm are preferably used. Fatty acid partial esters with a sodium metal content of less than 1 ppm can be produced by producing fatty acid partial esters by a conventional method and then purifying them by molecular distillation or the like.

[0064] Specifically, one method involves removing gases and low-boiling substances using a spray nozzle degasser, then removing polyhydric alcohols such as glycerin using a falling film distillation apparatus at a distillation temperature of 120 to 150°C and a vacuum of 0.01 to 0.03 kPa, and then using a centrifugal molecular distillation apparatus at a distillation temperature of 160 to 230°C and a vacuum of 0.01 to 0.2 Torr to obtain a high-purity fatty acid partial ester as a distillate, with sodium metal being removed as a distillation residue. Repeated molecular distillation of the obtained distillate can further increase the purity and produce a fatty acid partial ester with an even lower sodium metal content. It is also important to thoroughly clean the inside of the molecular distillation apparatus in advance using an appropriate method and to increase the airtightness to prevent contamination with sodium metal components from the external environment. Such fatty acid esters are available from specialist suppliers (e.g., Riken Vitamin Co., Ltd.).

[0065] (ii) Phosphorus-based stabilizers: The recycled polycarbonate resin (raw material) used in the present invention may further contain various phosphorus-based stabilizers, primarily for the purpose of improving its thermal stability during molding. Examples of such phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid, and esters thereof. Further, such phosphorus-based stabilizers include tertiary phosphines.

[0066] Specific examples of the phosphite compound include triphenyl phosphite, tris(nonylphenyl)phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, tris(diethylphenyl)phosphite, tris(di-iso-propylphenyl)phosphite, and tris(di-n-butylphenyl)phosphite. bis(2,6-di-tert-butylphenyl)pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(2,6-di-tert-butylphenyl)phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, dicyclohexyl pentaerythritol diphosphite, and the like.

[0067] Further, other phosphite compounds that react with dihydric phenols to form a cyclic structure may be used, such as 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2,4-di-tert-butylphenyl)phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, 2,2'-methylenebis(4-methyl-6-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, and 2,2'-ethylidenebis(4-methyl-6-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite.

[0068] Examples of the phosphate compound include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, and diisopropyl phosphate, and preferred are triphenyl phosphate and trimethyl phosphate.

[0069] Examples of the phosphonite compounds include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, bis(2,4-di-tert-butylphenyl)-4-phenyl ... Examples of suitable phosphonite compounds include (2,4-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite, bis(2,6-di-n-butylphenyl)-3-phenyl-phenyl phosphonite, bis(2,6-di-tert-butylphenyl)-4-phenyl-phenyl phosphonite, and bis(2,6-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite. Preferred are tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenyl phosphonite, with tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenyl phosphonite being more preferred. Such phosphonite compounds can be used in combination with, and are preferred for, the above-mentioned phosphite compounds having an aryl group substituted with two or more alkyl groups.

[0070] Examples of phosphonate compounds include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate. Examples of tertiary phosphines include triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triamylphosphine, dimethylphenylphosphine, dibutylphenylphosphine, diphenylmethylphosphine, diphenyloctylphosphine, triphenylphosphine, tri-p-tolylphosphine, trinaphthylphosphine, and diphenylbenzylphosphine. A particularly preferred tertiary phosphine is triphenylphosphine.

[0071] The phosphorus-based stabilizers may be used alone or in combination of two or more. Among the phosphorus-based stabilizers, phosphite compounds or phosphonite compounds are preferred. Tris(2,4-di-tert-butylphenyl)phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite are particularly preferred. The combined use of these with a phosphate compound is also a preferred embodiment.

[0072] (iii) Hindered phenol-based stabilizers (antioxidants) The recycled polycarbonate resin (raw material) used in the present invention may contain a hindered phenol-based stabilizer blended therein for the primary purpose of improving its thermal stability during molding and heat aging resistance. Examples of such hindered phenol-based stabilizers include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, and 2,6-di-tert-butyl-4-(N,N-dimethylaminomethyl) Phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-dimethylene-bis(6-α-methyl-benzyl -p-cresol)2,2'-ethylidene-bis(4,6-di-tert-butylphenol), 2,2'-butylidene-bis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), triethylene glycol-N-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] hydroxyphenyl)propionate], bis[2-tert-butyl-4-methyl 6-(3-tert-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1,-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4,4'-di-thiobis(2,6-di-tert-butylphenol), 4,4'-tri-thiobis(2,6-di-tert-butylphenol), 2,2-thiodiethylenebis-[3- (3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3',5'-di-tert-butylanilino)-1,3,5-triazine, N,N'-hexamethylenebis-(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl]hydrazine, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxyphenyl)isocyanurate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, and tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane. All of these are readily available. The above hindered phenol-based antioxidants may be used alone or in combination of two or more.

[0073] The (ii) phosphorus-based stabilizer and / or (iii) hindered phenol-based antioxidant may be contained in an amount of preferably 0.0001 to 1 part by weight, more preferably 0.001 to 0.5 parts by weight, and even more preferably 0.005 to 0.1 part by weight, per 100 parts by weight of the recycled polycarbonate resin (raw material). If the amount of stabilizer is less than the above range, it is difficult to obtain a good stabilizing effect, and if the amount is greater than the above range, the physical properties of the material may deteriorate and the mold may be contaminated during molding.

[0074] The recycled polycarbonate resin (raw material) used in the present invention may contain antioxidants other than the above-mentioned hindered phenol-based antioxidants. Examples of such antioxidants include pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-laurylthiopropionate), and glycerol-3-stearylthiopropionate. These other antioxidants may be contained in an amount of 0.001 to 0.05 parts by weight per 100 parts by weight of the recycled polycarbonate resin (raw material).

[0075] (iv) Ultraviolet Absorber The recycled polycarbonate resin (raw material) used in the present invention may contain an ultraviolet absorber. Specific examples of the ultraviolet absorber include benzophenone-based ones such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxytrihydridolatebenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sodium sulfoxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-hydroxy-4-n-dodecyloxybenzophenone, and 2-hydroxy-4-methoxy-2'-carboxybenzophenone.

[0076] Specific examples of the ultraviolet absorber include benzotriazole-based compounds such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dicumylphenyl)phenylbenzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, Examples of the 2-hydroxyphenyl-2H-benzotriazole skeleton include 2-(2-hydroxy-5-acryloxyethylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-4-octoxyphenyl)benzotriazole, 2,2'-methylenebis(4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis(1,3-benzoxazin-4-one), and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, and polymers having a 2-hydroxyphenyl-2H-benzotriazole skeleton such as copolymers of 2-(2'-hydroxy-5-methacryloxyethylphenyl)-2H-benzotriazole and vinyl monomers copolymerizable with the monomer, and copolymers of 2-(2'-hydroxy-5-acryloxyethylphenyl)-2H-benzotriazole and vinyl monomers copolymerizable with the monomer.

[0077] Specific examples of hydroxyphenyltriazine ultraviolet absorbers include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-methyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-ethyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-propyloxyphenol, and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-butyloxyphenol. Further examples include compounds in which the phenyl group of the above-mentioned compounds is replaced with a 2,4-dimethylphenyl group, such as 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hexyloxyphenol.

[0078] Specific examples of cyclic iminoester-based ultraviolet absorbers include 2,2'-p-phenylenebis(3,1-benzoxazin-4-one), 2,2'-(4,4'-diphenylene)bis(3,1-benzoxazin-4-one), and 2,2'-(2,6-naphthalene)bis(3,1-benzoxazin-4-one). Specific examples of cyanoacrylate-based ultraviolet absorbers include 1,3-bis-[(2'-cyano-3',3'-diphenylacryloyl)oxy]-2,2-bis[(2-cyano-3,3-diphenylacryloyl)oxy]methyl)propane and 1,3-bis-[(2-cyano-3,3-diphenylacryloyl)oxy]benzene.

[0079] Furthermore, the ultraviolet absorber may be a polymeric ultraviolet absorber obtained by copolymerizing such an ultraviolet absorbing monomer and / or a photostable monomer having a hindered amine structure with a monomer such as alkyl(meth)acrylate by adopting a structure of a radically polymerizable monomer compound. Suitable examples of the ultraviolet absorbing monomer include compounds containing a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a cyclic iminoester skeleton, and a cyanoacrylate skeleton in the ester substituent of a (meth)acrylic acid ester.

[0080] Among the above, benzotriazole-based and hydroxyphenyltriazine-based absorbers are preferred in terms of UV absorption ability, while cyclic iminoester-based and cyanoacrylate-based absorbers are preferred in terms of heat resistance and color. The above UV absorbers may be used alone or in a mixture of two or more. The UV absorber may be contained in an amount of preferably 0.01 to 2 parts by weight, more preferably 0.03 to 2 parts by weight, even more preferably 0.04 to 1 part by weight, and particularly preferably 0.05 to 0.5 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material).

[0081] (v) Flow Modifiers: The recycled polycarbonate resin (raw material) used in the present invention may contain a flow modifier, provided that the effects of the present invention are not impaired. Suitable examples of such flow modifiers include styrene oligomers, polycarbonate oligomers (including highly branched, hyperbranched, and cyclic oligomers), polyalkylene terephthalate oligomers (including highly branched, hyperbranched, and cyclic oligomers), highly branched and hyperbranched aliphatic polyester oligomers, terpene resins, and polycaprolactone. The amount of such flow modifier per 100 parts by weight of the recycled polycarbonate resin (raw material) is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, and even more preferably 2 to 15 parts by weight. Polycaprolactone is particularly preferred, and may be contained in a composition ratio of 2 to 7 parts by weight, particularly preferably, per 100 parts by weight of the recycled polycarbonate resin (raw material). The molecular weight of polycaprolactone, expressed as a number average molecular weight, is preferably 1,000 to 70,000, more preferably 1,500 to 40,000, even more preferably 2,000 to 30,000, and most preferably 2,500 to 15,000.

[0082] (vi) Antistatic Agents: The recycled polycarbonate resin (raw material) used in the present invention may contain an antistatic agent, primarily for the purpose of improving antistatic properties. Examples of antistatic agents that can be used include phosphonium sulfonates, phosphites, and caprolactone-based polymers, with phosphonium sulfonates being preferred. Specific examples of such phosphonium sulfonates include tetrabutylphosphonium dodecylsulfonate, tetrabutylphosphonium dodecylbenzenesulfonate, tributyloctylphosphonium dodecylbenzenesulfonate, tetraoctylphosphonium dodecylbenzenesulfonate, tetraethylphosphonium octadecylbenzenesulfonate, tributylmethylphosphonium dibutylbenzenesulfonate, triphenylphosphonium dibutylnaphthylsulfonate, and trioctylmethylphosphonium diisopropylnaphthylsulfonate. Among these, tetrabutylphosphonium dodecylbenzenesulfonate is preferred due to its compatibility with polycarbonate and easy availability. The antistatic agent may be contained in an amount of preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight, even more preferably 0.3 to 2.0 parts by weight, and particularly preferably 0.5 to 1.8 parts by weight, per 100 parts by weight of the recycled polycarbonate resin (raw material). At or above the lower limit, the antistatic effect of the polycarbonate resin is obtained, while at or below the upper limit, the transparency and mechanical strength of the polycarbonate resin are excellent, and no silver smear or peeling occurs on the surface of the molded article, making it less likely to cause poor appearance.

[0083] The recycled polycarbonate resin (raw material) used in the present invention may also contain various additives such as bluing agents, fluorescent dyes, flame retardants, and dyes and pigments. These additives can be appropriately selected and used as long as they do not impair the effects of the present invention. The recycled polycarbonate resin (raw material) may contain a bluing agent in an amount of preferably 0.05 to 3.0 ppm (by weight). Representative examples of bluing agents include Bayer's Macrolex Violet B and Macrolex Blue RR, and Clariant's Polythren Blue RLS.

[0084] Examples of fluorescent dyes (including fluorescent brighteners) include coumarin-based fluorescent dyes, benzopyran-based fluorescent dyes, perylene-based fluorescent dyes, anthraquinone-based fluorescent dyes, thioindigo-based fluorescent dyes, xanthene-based fluorescent dyes, xanthone-based fluorescent dyes, thioxanthene-based fluorescent dyes, thioxanthone-based fluorescent dyes, thiazine-based fluorescent dyes, and diaminostilbene-based fluorescent dyes. Fluorescent dyes (including fluorescent brighteners) may be contained in an amount of preferably 0.0001 to 0.1 parts by weight per 100 parts by weight of the recycled polycarbonate resin (raw material).

[0085] Examples of flame retardants include metal sulfonate flame retardants, halogen-containing compound flame retardants, phosphorus-containing compound flame retardants, and silicon-containing compound flame retardants. Among these, metal sulfonate flame retardants are preferred. The flame retardant may be contained in an amount of preferably 0.01 to 1 part by weight, more preferably 0.05 to 1 part by weight, per 100 parts by weight of the recycled polycarbonate resin (raw material).

[0086] <Method for Producing Recycled Polycarbonate Resin Particles> <Aspect 1> In the present invention, the following method is preferably employed as a method for producing recycled polycarbonate resin particles characterized in that the amount of oligomers determined by gel permeation chromatography (GPC) is 1.4% or less and the molecular weight distribution (Mw / Mn) is 2.3 or less.

[0087] <Solvent Extraction> In the method for producing recycled polycarbonate resin particles of the present invention, solvent extraction is performed to remove low-molecular-weight impurities such as monomers, oligomers, additives, and modified products thereof from the recycled polycarbonate resin (raw material). Solvent extraction involves dissolving the monomers, oligomers, additives, and modified products thereof present in the recycled polycarbonate resin (raw material) into an organic solvent, separating the solid from the liquid, and drying at 80 to 140°C to obtain the recycled polycarbonate resin particles of the present invention. The organic solvent used and separated in the extraction can be reused repeatedly, usually after industrial distillation to remove the eluted material.

[0088] The extraction method using an organic solvent can be either (i) a batch method or (ii) a continuous method. (i) The batch method, as disclosed in, for example, Japanese Patent Application Laid-Open Nos. 63-278929 and 64-6020, involves placing a polycarbonate powder and an organic solvent in a vessel, stirring, and then separating the solid from the liquid. (ii) The continuous method, as disclosed in, for example, Japanese Patent Application Laid-Open Nos. 4-306227 and 4-145903, is a production method in which, when extracting impurities from a polycarbonate powder with an organic solvent, the polycarbonate powder is introduced from the top of an extraction vessel while the organic solvent is introduced from the bottom of the extraction vessel, and while continuous countercurrent contact is maintained, the organic solvent is discharged from the top of the extraction vessel, and the polycarbonate powder is allowed to settle naturally in the organic solvent without stirring, and is removed from the bottom of the extraction vessel in the form of a slurry, followed by solid-liquid separation and drying. As reported in JP-A-4-306227, the batch process (i) is inefficient for industrial use and has the drawback that prolonged stirring generates fine polycarbonate powder, inhibiting the efficiency of solid-liquid separation. Furthermore, it has been confirmed that repeated separation, recovery, and reuse of acetone used as an organic solvent gradually increases the amount of residual methylene chloride in the dry powder obtained by acetone extraction. For these reasons, it is preferable to employ the continuous process (ii) industrially.

[0089] The organic solvent used in the solvent extraction of the present invention has a solubility parameter of 16 to 30 MPa. ０．５ It is preferable to use an organic solvent of 17 to 25 MPa. ０．５ More preferably, 18 to 22 MPa ０．５ Within the above range, monomers, oligomers, additives, and modified products thereof present in the recycled polycarbonate resin (raw material) can be efficiently extracted.

[0090] Solubility parameter (sometimes called δ or SP value). Units are (MPa ０．５ ) is a value defined by the regular solution theory introduced by Hildebrand, and is calculated from the molar heat of vaporization and molar volume of the compound. ０．５ Examples of organic solvents that can be used include compounds having a carbonyl group such as acetone, methyl ethyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, and diethyl ketone; compounds having an acetyl group such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and vinyl acetate; alkyl ethers such as diethyl ether and dibutyl ether; alcohols such as methanol, ethanol, isopropyl alcohol, 1-propanol, 1-butanol, and methoxypropanol; and aromatic hydrocarbons such as ethylbenzene, paraxylene, and mesitylene. Among these, acetone is more preferred because it can efficiently extract monomers, oligomers, additives, and modified products thereof, and has a low boiling point that makes it easy to separate and recover them by distillation. Furthermore, two or more of these organic solvents can be used in combination, as needed.

[0091] The contact time with the organic solvent in the solvent extraction of the present invention is simply the processing time in the case of a batch system, but in the case of a continuous system, for example, when the recycled polycarbonate resin (raw material) is charged from the top of an extraction vessel while the organic solvent is introduced from the bottom of the extraction vessel and continuous countercurrent contact is carried out, the organic solvent is discharged from the top of the extraction vessel, and the recycled polycarbonate resin particles are allowed to settle naturally in the organic solvent while maintaining a constant liquid volume in the extraction vessel and are taken out from the bottom of the extraction vessel in the form of a slurry, the contact time is expressed by the following formula (2): Contact time (hr) = Liquid volume in extraction vessel (m ３ ) / resin and organic solvent input (= removal) speed (m ３ / hr)...(2)

[0092] In the solvent extraction of the present invention, the contact time with the organic solvent is preferably 10 minutes to 7 hours, more preferably 30 minutes to 7 hours, even more preferably 1 hour to 6 hours, and particularly preferably 2 hours to 6 hours in the case of a batch system, and is preferably 10 minutes to 7 hours, more preferably 10 minutes to 3 hours, even more preferably 20 minutes to 2 hours, and particularly preferably 30 minutes to 1 hour in the case of a continuous system. Within the above ranges, monomers, oligomers, additives, and modified products thereof can be efficiently extracted, and are therefore industrially preferred.

[0093] The temperature of the organic solvent introduced has a significant effect on the extraction efficiency and is usually set to a temperature not higher than the boiling point of the organic solvent used, preferably 10 to 100°C, more preferably 30 to 80°C. When acetone is used as the organic solvent, the temperature is preferably 10 to 55°C, more preferably 30 to 50°C, and the extractor is preferably equipped with a jacket or a heat-retaining mechanism.

[0094] The recycled polycarbonate resin (raw material) used in the solvent extraction of the present invention is primarily injection-molded polycarbonate resin products, crushed sprues or runners generated during injection molding, extrusion-molded products such as films and sheets, crushed scraps generated during extrusion molding, and pellets produced from these crushed materials in an extruder. Many of these are amorphous and may fuse instantly upon contact with organic solvents. To ensure sufficient contact area with the organic solvent and prevent fusion, the recycled polycarbonate resin (raw material) used in the present invention is preferably particulate, with an average major axis of 200 to 5,000 μm, more preferably 250 to 4,500 μm. The average particle size of the recycled polycarbonate resin (raw material) is preferably 0.1 to 5 mm, more preferably 0.15 to 4 mm, and even more preferably 0.2 to 3 mm.

[0095] The recycled polycarbonate resin (raw material) having the above average major axis and average particle size may be produced by known methods including mechanical pulverization and wet pulverization, or commercially available products may be used. In the mechanical pulverization method, for example, the recycled polycarbonate resin (raw material) is mechanically pulverized to produce particles having the desired average major axis and average particle size. According to the mechanical pulverization method, recycled polycarbonate resin (raw material) particles can be produced, for example, by the following method.

[0096] The recycled polycarbonate resin (raw material) may be pulverized after freezing or at room temperature. Mechanical pulverization can be carried out using known equipment for pulverizing recycled polycarbonate resin (raw material). Examples of such equipment include compression pulverizers (e.g., roll crushers), impact pulverizers (e.g., impact crushers, hammer mills), cutting or shear pulverizers (e.g., cutter mills, reciprocating pulverizers, low-speed rotary pulverizers (e.g., biaxial shear pulverizers)), impact shear pulverizers (e.g., shredders), and various fine pulverizers (e.g., ball mills, disk mills, pin mills, hammer mills, turbo mills, jet mills). Among these, cutting or shear pulverizers are preferred because they can directly feed molded products, have excellent pulverization efficiency, and can accommodate the required particle size. Among these, low-speed rotary pulverizers are preferred because they can easily produce desirable pulverized products with an appropriate bulk density, even for highly tough exterior molded products. Any type of low-speed rotary pulverizer, such as a single-axis, double-axis, or triaxial type, can be used. In the mechanical pulverization method, the frictional heat generated by the recycled polycarbonate resin (raw material) during pulverization may cause the recycled polycarbonate resin (raw material) to fuse together, making it impossible to obtain particles with the desired average major axis or average particle size. Therefore, the thermoplastic resin may be cooled and embrittled using liquid nitrogen or the like before being pulverized.

[0097] According to the mechanical pulverization method, the average major axis and average particle size of the produced particles can be adjusted to a desired range by appropriately adjusting the amount of solvent relative to the recycled polycarbonate resin (raw material), or the pulverization method or speed. In the wet method, for example, a dispersion in which the recycled polycarbonate resin (raw material) is dispersed using a surfactant or the like is dried to obtain particles having the desired average major axis and average particle size. The slurry discharged by solvent extraction is preferably filtered, centrifuged, or the like to remove the organic solvent, and then dried to obtain the recycled polycarbonate resin particles of the present invention.

[0098] The dryer may be of a conductive heating type or a hot air drying type, and the recycled polycarbonate resin particles may be left standing, transported, or stirred. Among them, a channel or cylindrical dryer that stirs the recycled polycarbonate resin particles using a conductive heating type is preferred, and a channel dryer is particularly preferred. The drying temperature is preferably in the range of 80 to 140°C.

[0099] <Filtration Treatment> In order to reduce the amount of foreign matter in the recycled polycarbonate resin particles, the recycled polycarbonate resin particles of the present invention obtained by solvent extraction may be dissolved in a halogenated hydrocarbon solvent, the recycled polycarbonate resin solution may be filtered, and the halogenated hydrocarbon solvent may be removed to obtain recycled polycarbonate resin particles. The halogenated hydrocarbon solvent used in this process is a good solvent for polycarbonate resin and is immiscible with water. The halogenated hydrocarbon solvent referred to in the present invention is a solvent primarily composed of at least one good solvent, preferably 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, etc. Methylene chloride (boiling point at atmospheric pressure: 40°C) is particularly preferred. As such a halogenated hydrocarbon solvent, a solvent in which 90% by volume or more of the solvent is a good solvent is preferably used, and a solvent essentially consisting of a good solvent is particularly preferred.

[0100] In this case, the concentration of the recycled polycarbonate resin solution is preferably 5 to 30% by weight, more preferably 5 to 25% by weight, because a concentration within this range provides an appropriate solution concentration, is easy to handle in industrial production facilities, is easy to wash the solution, has good filtration efficiency, and does not contain too much halogenated hydrocarbon solvent, so that subsequent removal of the solvent does not require excessive energy, which is advantageous from the standpoint of economical production.

[0101] Furthermore, the halogenated hydrocarbon solvent used in the present invention may contain a poor solvent to the extent that the polymer does not precipitate. Examples of such poor solvents include aliphatic hydrocarbons such as pentane, hexane, and heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene. The recycled polycarbonate resin solution after filtration is granulated and dried to obtain the recycled polycarbonate resin particles of the present invention. There are no particular limitations on the granulation and drying methods, and known methods can be used.

[0102] <Washing Treatment> For the purpose of reducing impurities in the recycled polycarbonate resin particles, the recycled polycarbonate resin particles of the present invention obtained by solvent extraction may be dissolved in a halogenated hydrocarbon solvent, and the recycled polycarbonate resin solution may be subjected to one or more treatments selected from water washing, acid washing, and alkali washing before and / or after filtering the recycled polycarbonate resin solution, and then the halogenated hydrocarbon solvent may be removed to obtain recycled polycarbonate resin particles.

[0103] The washing treatment involves dissolving the recycled polycarbonate resin in a halogenated hydrocarbon solvent, mixing the recycled polycarbonate resin solution with water, acid, or alkali, stirring the mixture, and then separating the organic solvent solution phase from the aqueous phase by leaving the mixture to stand or using a centrifuge, etc., and repeatedly removing the organic solvent solution phase to remove water-soluble impurities. Water washing, acid washing, and alkali washing can be performed in any order and combination. When acid washing or alkali washing is performed, water washing is performed until the electrical conductivity of the aqueous phase is preferably 50 μS / cm or less, more preferably 10 μS / cm or less. By performing water, acid, or alkali washing, water-soluble impurities are removed, and the color of the resulting recycled polycarbonate resin is improved. The washing treatment may be performed either before or after filtration. The recycled polycarbonate resin solution after washing is granulated and dried to obtain the recycled polycarbonate resin particles of the present invention. There are no particular limitations on the granulation and drying methods, and known methods can be used.

[0104] <Recycled Polycarbonate Resin Particles> In the recycled polycarbonate resin particles of the present invention, the particle shape is not particularly limited, but similarly to the above-described recycled polycarbonate resin (raw material), from the viewpoint of ease of handling, etc., the average major axis is preferably 200 to 5000 μm, more preferably 250 to 4500 μm, and the average particle size is preferably 0.1 to 5 mm, more preferably 0.15 to 4 mm, and even more preferably 0.2 to 3 mm.

[0105] <Molecular Weight Distribution> The recycled polycarbonate resin particles of the present invention have a molecular weight distribution (Mw / Mn) expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of 2.3 or less, preferably 2.25 or less, and more preferably 2.2 or less. Within the above range, the impact resistance of molded articles obtained from the recycled polycarbonate resin particles is favorable, which is preferable. In addition, the lower limit of the molecular weight distribution (Mw / Mn) is not particularly limited, but is preferably 1.1 or more, 1.3 or more, 1.5 or more, 1.7 or more, 1.9 or more, or 2.0 or more.

[0106] In the present invention, Mw and Mn were measured by dissolving 10 mg of a sample in 5 ml of chloroform and introducing 5 μl of the solution into a gel permeation chromatography (GPC) apparatus under the following conditions: (Measurement conditions) Apparatus: GPC system (HLC-8420GPC) manufactured by Tosoh Corporation Detector: CH-2 (UV) Column: TSKgel super HZM-M Flow rate: 0.35 mL / min Column temperature: 40.0°C Standard substance: TSK standard polystyrene Eluent: Chloroform

[0107] <Oligomer content> The oligomer content of the recycled polycarbonate resin particles in the present invention is 1.4% or less, preferably 1.2% or less, more preferably 1.0% or less, even more preferably 0.8% or less, and particularly preferably 0.6% or less. Within the above range, the impact resistance of molded articles obtained from the recycled polycarbonate resin particles is improved, which is preferable. In addition, the lower limit of the oligomer content is not particularly limited, but is preferably 0.01% or more, 0.05% or more, 0.1% or more, or 0.15% or more.

[0108] The amount of oligomer in the present invention was determined by dissolving 50 mg of a sample in 5 ml of chloroform, introducing 20 μl of the solution into a GPC apparatus under the following conditions, and measuring the ratio (%) of the peak area of ​​oligomer components (number average molecular weight in polystyrene equivalent of less than 6,000) observed at retention times of 7.5 minutes or later in the GPC chart to the total peak area, and the ratio was calculated as area %, and includes monomers, oligomers, additives, and modified products thereof. (Measurement Conditions) Apparatus: GPC system (Waters 2695) manufactured by Waters Corporation Column: TSKgel Super H3000 manufactured by Tosoh Corporation Flow rate: 0.6 mL / min Detector: Waters 2487 manufactured by Tosoh Corporation Detection conditions: UV 254 nm Column temperature: 40.0° C. Standard substance: TSK standard polystyrene Eluent: Chloroform

[0109] <Additive Amount> In the recycled polycarbonate resin particles of the present invention, it is preferable that the residual amount of various additives is reduced, since this makes it easier to prepare materials suitable for various applications when reusing the recycled polycarbonate resin particles. In particular, the recycled polycarbonate resin particles of the present invention preferably have a total amount of benzotriazole-based UV absorbers with a molecular weight of 1000 or less of 1000 ppm or less, more preferably 700 ppm or less, even more preferably 500 ppm or less, and particularly preferably 300 ppm or less. If a large amount of low-molecular-weight benzotriazole-based UV absorbers or their modified products remains, molding defects such as mold contamination and deterioration of the color of the molded plate are likely to occur. In addition, the lower limit of the total amount of benzotriazole-based UV absorbers with a molecular weight of 1000 or less is not particularly limited, but is preferably 1 ppm or more, 5 ppm or more, 10 ppm or more, 20 ppm or more, or 30 ppm or more.

[0110] In addition, in order to facilitate adjustment of thermal stability, the recycled polycarbonate resin particles of the present invention preferably have a residual heat stabilizer content of 1500 ppm or less, more preferably 1000 ppm or less, even more preferably 700 ppm or less, and particularly preferably 500 ppm or less. The lower limit of the total amount of heat stabilizer is not particularly limited, but is preferably 5 ppm or more, 10 ppm or more, 20 ppm or more, 30 ppm or more, 40 ppm or more, or 50 ppm or more.

[0111] In the recycled polycarbonate resin particles of the present invention, the amount of residual release agent is preferably 1000 ppm or less, more preferably 700 ppm or less, even more preferably 500 ppm or less, and particularly preferably 300 ppm or less, from the viewpoint of ease of adjusting the release properties. The lower limit of the total amount of release agent is not particularly limited, but is preferably 5 ppm or more, 10 ppm or more, 20 ppm or more, or 30 ppm or more.

[0112] In the recycled polycarbonate resin particles of the present invention, the amount of residual colorant is preferably 0.4 ppm or less, more preferably 0.3 ppm or less, even more preferably 0.2 ppm or less, and particularly preferably 0.1 ppm or less, from the viewpoint of ease of adjusting the hue. The lower limit of the total amount of colorant is not particularly limited, but is preferably 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, or 0.03 ppm or more.

[0113] Furthermore, the recycled polycarbonate resin particles of the present invention preferably have a total content of the above-mentioned additives (ultraviolet absorber, heat stabilizer, release agent, colorant) of 3,000 ppm or less, more preferably 2,500 ppm or less, even more preferably 2,000 ppm or less, particularly preferably 1,500 ppm or less, and most preferably 1,000 ppm or less. The lower limit of the total content of the additives is not particularly limited, but is preferably 10 ppm or more, 30 ppm or more, 50 ppm or more, 70 ppm or more, or 100 ppm or more.

[0114] The amount of each additive (ultraviolet absorber, release agent, heat stabilizer, colorant) in the recycled polycarbonate resin particles of the present invention was determined by dissolving the obtained recycled polycarbonate resin particles in dichloromethane, extracting low molecular weight components by poor solvent precipitation using hexane, and then measuring the amount of the extract using a JMN-ECZ400S manufactured by JEOL Ltd. １ The H-NMR spectrum was measured, and the amount of each additive (ultraviolet absorber, release agent, heat stabilizer, colorant) was calculated from the integrated value of the peak derived from each additive.

[0115] <Number of foreign matters> The recycled polycarbonate resin particles of the present invention preferably have a number of foreign matters insoluble in methylene chloride collected through a nylon mesh with a mesh size of 20 μm per 50 g of recycled polycarbonate resin particles of 1500 or less, 1300 or less, 1100 or less, 1000 or less, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 300 or less, or 200 or less. Within the above range, the transparency and appearance of the molded plate obtained using the recycled polycarbonate resin particles are good. The lower limit of the number of foreign matters is not particularly limited, but is preferably 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, or 60 or more.

[0116] The number of foreign matters in the present invention was measured by dissolving 50 g of the obtained recycled polycarbonate resin particles in dichloromethane, filtering the solution through a nylon mesh cloth with a mesh size of 20 μm, and then capturing and counting the number of foreign matters remaining on the nylon mesh cloth using an EDS (X-MaxN20 manufactured by Oxford Instruments) and an SEM (SU3900 manufactured by Hitachi High-Technologies) equipped with analysis software (AZtec manufactured by Oxford Instruments).

[0117] The recycled polycarbonate resin particles of the present invention can be used by blending with virgin polycarbonate resin within a range that does not impair the properties of the present invention, and can be used by blending 5 to 100% by weight, 10 to 100% by weight, 20 to 100% by weight, 30 to 100% by weight, 40 to 100% by weight, or 50 to 100% by weight of recycled polycarbonate resin particles with 0 to 95% by weight, 0 to 90% by weight, 0 to 80% by weight, 0 to 70% by weight, 0 to 60% by weight, or 0 to 50% by weight of virgin polycarbonate resin.

[0118] The recycled polycarbonate resin particles of the present invention may further contain, as appropriate, modifiers such as heat stabilizers, antioxidants, release agents (fatty acid esters, etc.), weathering agents (ultraviolet absorbers), nucleating agents, lubricants, plasticizers, antistatic agents, thickeners, antibacterial agents, colorants (pigments, dyes), fillers, reinforcing agents, polymers such as other resins and rubbers, and flame retardants, within the range that does not impair the properties of the present invention. The blending amounts thereof are the same as the ranges of the content of additives in the recycled polycarbonate resin (raw material) described above.

[0119] <<Aspect 2>> In the present invention, the amount of oligomers determined by gel permeation chromatography (GPC) is 0.8% or less, the molecular weight distribution (Mw / Mn) is 2.3 or less, and the specific surface area measured by gas adsorption method is 0.05 to 1.2 g / cm ３ The following method is preferably employed as a method for producing recycled polycarbonate resin particles characterized by the above: First, recycled polycarbonate resin (raw material) before solvent extraction treatment is preferably subjected to filtration treatment, washing treatment and granulation to prepare recycled polycarbonate resin (raw material) having a specific surface area within a specific range.

[0120] <Filtration Treatment> For the purpose of reducing impurities in recycled polycarbonate resin (raw material), the recycled polycarbonate resin (raw material) may be dissolved in a halogenated hydrocarbon solvent, the recycled polycarbonate resin (raw material) solution filtered, and the halogenated hydrocarbon solvent removed to obtain recycled polycarbonate resin powder. The halogenated hydrocarbon solvent used in this process is a good solvent for polycarbonate resin and is immiscible with water. The halogenated hydrocarbon solvent referred to in the present invention is a solvent primarily composed of at least one good solvent, preferably 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, etc. Methylene chloride (boiling point at atmospheric pressure: 40°C) is particularly preferred. As such halogenated hydrocarbon solvents, solvents in which 90% by volume or more of the solvent is good solvent are preferably used, and solvents consisting essentially of good solvents are particularly preferred.

[0121] In this case, the concentration of the recycled polycarbonate resin (raw material) solution is preferably 5 to 30% by weight, more preferably 5 to 25% by weight. A concentration within this range provides an appropriate solution concentration, ease of handling in industrial production facilities, easy solution washing, and good filtration efficiency. Furthermore, the halogenated hydrocarbon solvent is not too high, so that subsequent solvent removal does not require excessive energy, which is advantageous from the standpoint of economical production. Furthermore, the halogenated hydrocarbon solvent used in the present invention may contain a poor solvent to the extent that it does not precipitate the polymer. Examples of such poor solvents include aliphatic hydrocarbons such as pentane, hexane, and heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

[0122] <Washing Treatment> For the purpose of reducing impurities in the recycled polycarbonate resin (raw material), the recycled polycarbonate resin (raw material) may be dissolved in a halogenated hydrocarbon solvent, and the recycled polycarbonate resin (raw material) solution may be subjected to one or more treatments of water washing, acid washing, and alkali washing before and / or after filtering the recycled polycarbonate resin (raw material) solution, and then the halogenated hydrocarbon solvent may be removed to obtain a recycled polycarbonate resin powder.

[0123] The washing treatment involves dissolving the recycled polycarbonate resin (raw material) in a halogenated hydrocarbon solvent, mixing and stirring the recycled polycarbonate resin (raw material) solution with water, acid, or alkali, and then separating the organic solvent solution phase from the aqueous phase by leaving the solution to stand or using a centrifuge or the like. The organic solvent solution phase is then repeatedly removed to remove water-soluble impurities. Water washing, acid washing, and alkali washing can be performed in any order and combination. When acid washing or alkali washing is performed, water washing is performed until the electrical conductivity of the aqueous phase is preferably 50 μS / cm or less, more preferably 10 μS / cm or less. By performing water, acid, or alkali washing, water-soluble impurities are removed, and the resulting recycled polycarbonate resin has a good color. The washing treatment may be performed either before or after the filtration treatment.

[0124] <Granulation Step> Any method can be used to produce a porous recycled polycarbonate resin powder having a large specific surface area from a filtered or washed recycled polycarbonate resin (raw material) solution. Examples include a method of spraying a polycarbonate solution into turbulent hot water (Japanese Patent Publication No. 40-3533), a method of spraying a polycarbonate solution into warm water at about 70°C (Japanese Patent Publication No. 46-37424), a method of supplying a polycarbonate solution together with steam to polycarbonate granules (Japanese Patent Publication No. 60-54329), a method of adding a polycarbonate solution having a concentration of 25 to 40% by weight to warm water at 60 to 80°C (Japanese Patent Laid-Open No. 60-54329), and a method of adding a low-boiling non-solvent to a polycarbonate solution (Japanese Patent Publication No. 42-1435, Japanese Patent Publication No. 46-31468).

[0125] The specific surface area of ​​the recycled polycarbonate resin powder obtained in the granulation process before solvent extraction, measured by the gas adsorption method, is 0.06 to 1.5 g / cm ３ is preferably 0.08 to 1.0 g / cm ３ , more preferably 0.1 to 0.6 g / cm ３ Within the above range, monomers, oligomers, additives, and modified products thereof can be efficiently extracted, which is industrially preferable. The bulk density of the recycled polycarbonate resin powder before solvent extraction is 0.2 to 0.8 g / cm. ３ is preferably 0.3 to 0.7 g / cm ３ Powders with a bulk density below the lower limit have a significantly increased extraction volume and a large number of internal pores, which can make it difficult for the powder to settle naturally in the solvent during continuous solvent extraction. Powders with a bulk density above the upper limit have insufficient internal pores, which can reduce the efficiency of solvent extraction and make it difficult to remove the organic solvent by drying.

[0126] <Solvent Extraction> In the method for producing recycled polycarbonate resin particles of the present invention, solvent extraction is performed to remove low-molecular-weight impurities such as monomers, oligomers, additives, and modified products thereof from the recycled polycarbonate resin (raw material). Solvent extraction involves dissolving the monomers, oligomers, additives, and modified products thereof present in the recycled polycarbonate resin (raw material) into an organic solvent, separating the solid from the liquid, and drying at 80 to 140°C to obtain the recycled polycarbonate resin particles of the present invention. The organic solvent used and separated in the extraction can be reused repeatedly, usually after industrial distillation to remove the eluted material.

[0127] The extraction method using an organic solvent can be either (i) a batch method or (ii) a continuous method. (i) The batch method, as disclosed in, for example, Japanese Patent Application Laid-Open Nos. 63-278929 and 64-6020, involves placing a polycarbonate powder and an organic solvent in a vessel, stirring, and then separating the solid from the liquid. (ii) The continuous method, as disclosed in, for example, Japanese Patent Application Laid-Open Nos. 4-306227 and 4-145903, is a production method in which, when extracting impurities from a polycarbonate powder with an organic solvent, the polycarbonate powder is introduced from the top of an extraction vessel while the organic solvent is introduced from the bottom of the extraction vessel, and while continuous countercurrent contact is maintained, the organic solvent is discharged from the top of the extraction vessel, and the polycarbonate powder is allowed to settle naturally in the organic solvent without stirring, and is removed from the bottom of the extraction vessel in the form of a slurry, followed by solid-liquid separation and drying. As reported in JP-A-4-306227, the batch process (i) is inefficient for industrial use and has the drawback that prolonged stirring generates fine polycarbonate powder, inhibiting the efficiency of solid-liquid separation. Furthermore, it has been confirmed that repeated separation, recovery, and reuse of acetone used as an organic solvent gradually increases the amount of residual methylene chloride in the dry powder obtained by acetone extraction. For these reasons, it is preferable to employ the continuous process (ii) industrially.

[0128] The organic solvent used in the solvent extraction of the present invention has a solubility parameter of 16 to 30 MPa. ０．５ It is preferable to use an organic solvent of 17 to 25 MPa. ０．５ More preferably, 18 to 22 MPa ０．５ Within the above range, monomers, oligomers, additives, and modified products thereof present in the recycled polycarbonate resin (raw material) can be efficiently extracted.

[0129] Solubility parameter (sometimes called δ or SP value). Units are (MPa ０．５) is a value defined by the regular solution theory introduced by Hildebrand, and is calculated from the molar heat of vaporization and molar volume of the compound. ０．５ Examples of organic solvents that can be used include compounds having a carbonyl group such as acetone, methyl ethyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, and diethyl ketone; compounds having an acetyl group such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and vinyl acetate; alkyl ethers such as diethyl ether and dibutyl ether; alcohols such as methanol, ethanol, isopropyl alcohol, 1-propanol, 1-butanol, and methoxypropanol; and aromatic hydrocarbons such as ethylbenzene, paraxylene, and mesitylene. Among these, acetone is more preferred because it can efficiently extract monomers, oligomers, additives, and modified products thereof, and has a low boiling point that makes it easy to separate and recover them by distillation. Furthermore, two or more of these organic solvents can be used in combination, as needed.

[0130] The contact time with the organic solvent in the solvent extraction of the present invention is simply the processing time in the case of a batch system, but in the case of a continuous system, for example, when the recycled polycarbonate resin (raw material) is charged from the top of an extraction vessel while the organic solvent is introduced from the bottom of the extraction vessel and continuous countercurrent contact is carried out, the organic solvent is discharged from the top of the extraction vessel, and the recycled polycarbonate resin is allowed to settle naturally in the organic solvent while maintaining a constant liquid volume in the extraction vessel and is then removed from the bottom of the extraction vessel in the form of a slurry, the contact time is expressed by the following formula (2): Contact time (hr) = Liquid volume in extraction vessel (m ３ ) / resin and organic solvent input (= removal) speed (m ３ / hr)...(2)

[0131] In the solvent extraction of the present invention, the contact time with the organic solvent is preferably 10 minutes to 7 hours, more preferably 30 minutes to 6 hours, even more preferably 30 minutes to 5 hours, particularly preferably 30 minutes to 4 hours, and most preferably 1 hour to 4 hours, in the case of a batch process. In the case of a continuous process, the contact time is preferably 3 minutes to 7 hours, more preferably 5 minutes to 5 hours, even more preferably 10 minutes to 3 hours, particularly preferably 10 minutes to 1.5 hours, and most preferably 20 minutes to 1 hour. Within the above ranges, monomers, oligomers, additives, and modified products thereof can be efficiently extracted, and is also industrially preferred.

[0132] The temperature of the organic solvent introduced has a significant effect on the extraction efficiency and is usually set to a temperature below the boiling point of the organic solvent used, preferably 10 to 100°C, more preferably 30 to 80°C. When acetone is used as the organic solvent, the temperature is preferably 10 to 55°C, more preferably 30 to 50°C, and the extraction apparatus is preferably equipped with a jacket or a heat retention mechanism. The organic solvent is removed from the slurry discharged by solvent extraction, preferably by filtration, centrifugation, or the like, and the slurry is then dried to obtain the recycled polycarbonate resin particles of the present invention.

[0133] The dryer may be of a conductive heating type or a hot air drying type, and the recycled polycarbonate resin particles may be left standing, transported, or stirred. Among them, a channel or cylindrical dryer that stirs the recycled polycarbonate resin particles using a conductive heating type is preferred, and a channel dryer is particularly preferred. The drying temperature is preferably in the range of 100 to 140°C.

[0134] <Recycled Polycarbonate Resin Particles> In the recycled polycarbonate resin particles of the present invention, from the viewpoints of efficiency of the solvent extraction treatment, ease of handling, etc., the specific surface area measured by the gas adsorption method is 0.05 to 1.2 g / cm ３ and 0.06 to 1.0 g / cm ３ is preferably 0.07 to 0.8 g / cm ３ More preferably, it is 0.08 to 0.6 g / cm ３ It is more preferable that:

[0135] The bulk density of the recycled polycarbonate resin particles is 0.2 to 0.8 g / cm ３ is preferably 0.3 to 0.75 g / cm ３ More preferably, it is 0.4 to 0.7 g / cm ３ It is more preferable that:

[0136] <Molecular Weight Distribution> The recycled polycarbonate resin particles of the present invention have a molecular weight distribution (Mw / Mn) expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of 2.3 or less, preferably 2.25 or less, and more preferably 2.2 or less. Within the above range, the impact resistance of molded articles obtained from the recycled polycarbonate resin particles is favorable, which is preferable. In addition, the lower limit of the molecular weight distribution (Mw / Mn) is not particularly limited, but is preferably 1.1 or more, 1.3 or more, 1.5 or more, 1.7 or more, 1.9 or more, or 2.0 or more.

[0137] In the present invention, Mw and Mn were measured by dissolving 10 mg of a sample in 5 ml of chloroform and introducing 5 μl of the solution into a gel permeation chromatography (GPC) apparatus under the following conditions: (Measurement conditions) Apparatus: GPC system (HLC-8420GPC) manufactured by Tosoh Corporation Detector: CH-2 (UV) Column: TSKgel super HZM-M Flow rate: 0.35 mL / min Column temperature: 40.0°C Standard substance: TSK standard polystyrene Eluent: Chloroform

[0138] <Oligomer content> The oligomer content of the recycled polycarbonate resin particles in the present invention is 0.8% or less, preferably 0.7% or less, more preferably 0.6% or less, even more preferably 0.5% or less, and particularly preferably 0.4% or less. Within the above range, the impact resistance of molded articles obtained from the recycled polycarbonate resin particles is improved, which is preferable. In addition, the lower limit of the oligomer content is not particularly limited, but is preferably 0.01% or more, 0.05% or more, 0.1% or more, 0.15% or more, or 0.2% or more.

[0139] The amount of oligomer in the present invention was determined by dissolving 50 mg of a sample in 5 ml of chloroform, introducing 20 μl of the solution into a GPC apparatus under the following conditions, and measuring the ratio (%) of the peak area of ​​oligomer components (number average molecular weight in polystyrene equivalent of less than 6,000) observed at retention times of 7.5 minutes or later in the GPC chart to the total peak area, and the ratio was calculated as area %, and includes monomers, oligomers, additives, and modified products thereof. (Measurement Conditions) Apparatus: GPC system (Waters 2695) manufactured by Waters Corporation Column: TSKgel Super H3000 manufactured by Tosoh Corporation Flow rate: 0.6 mL / min Detector: Waters 2487 manufactured by Tosoh Corporation Detection conditions: UV 254 nm Column temperature: 40.0° C. Standard substance: TSK standard polystyrene Eluent: Chloroform

[0140] <Additive Amount> In the recycled polycarbonate resin particles of the present invention, it is preferable that the residual amount of various additives is reduced, since this makes it easier to prepare materials suitable for various applications when reusing the recycled polycarbonate resin particles. In particular, the recycled polycarbonate resin particles of the present invention preferably have a total amount of benzotriazole-based UV absorbers with a molecular weight of 1000 or less of 500 ppm or less, more preferably 400 ppm or less, even more preferably 300 ppm or less, and particularly preferably 200 ppm or less. If a large amount of low-molecular-weight benzotriazole-based UV absorbers or their modified products remains, molding defects such as mold contamination and deterioration of the color of the molded plate are likely to occur. In addition, the lower limit of the total amount of benzotriazole-based UV absorbers with a molecular weight of 1000 or less is not particularly limited, but is preferably 1 ppm or more, 5 ppm or more, 10 ppm or more, 20 ppm or more, or 30 ppm or more.

[0141] In addition, in the recycled polycarbonate resin particles of the present invention, the amount of residual heat stabilizer is preferably 1000 ppm or less, more preferably 800 ppm or less, even more preferably 600 ppm or less, and particularly preferably 500 ppm or less, from the viewpoint of ease of adjusting thermal stability. The lower limit of the total amount of heat stabilizer is not particularly limited, but is preferably 5 ppm or more, 10 ppm or more, 20 ppm or more, or 30 ppm or more.

[0142] In the recycled polycarbonate resin particles of the present invention, the amount of residual release agent is preferably 700 ppm or less, more preferably 500 ppm or less, even more preferably 300 ppm or less, and particularly preferably 200 ppm or less, from the viewpoint of ease of adjusting the release properties. The lower limit of the total amount of release agent is not particularly limited, but is preferably 1 ppm or more, 3 ppm or more, 5 ppm or more, 10 ppm or more, or 15 ppm or more.

[0143] In the recycled polycarbonate resin particles of the present invention, the amount of residual colorant is preferably 0.4 ppm or less, more preferably 0.3 ppm or less, even more preferably 0.2 ppm or less, and particularly preferably 0.15 ppm or less, from the viewpoint of ease of adjusting the hue. The lower limit of the total amount of colorant is not particularly limited, but is preferably 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, or 0.03 ppm or more.

[0144] Furthermore, the recycled polycarbonate resin particles of the present invention preferably have a total content of the above-mentioned additives (ultraviolet absorber, heat stabilizer, release agent, colorant) of 3,000 ppm or less, more preferably 2,000 ppm or less, even more preferably 1,500 ppm or less, particularly preferably 1,000 ppm or less, and most preferably 800 ppm or less. The lower limit of the total content of the additives is not particularly limited, but is preferably 10 ppm or more, 30 ppm or more, 50 ppm or more, 100 ppm or more, or 200 ppm or more.

[0145] The amount of each additive (ultraviolet absorber, release agent, heat stabilizer, colorant) in the recycled polycarbonate resin particles of the present invention was determined by dissolving the obtained recycled polycarbonate resin particles in dichloromethane, extracting low molecular weight components by poor solvent precipitation using hexane, and then measuring the amount of the extract using a JMN-ECZ400S manufactured by JEOL Ltd. １ The H-NMR spectrum was measured, and the amount of each additive (ultraviolet absorber, release agent, heat stabilizer, colorant) was calculated from the integrated value of the peak derived from each additive.

[0146] <Number of foreign matters> The recycled polycarbonate resin particles of the present invention have a number of foreign matters insoluble in methylene chloride collected through a nylon mesh with a mesh size of 20 μm, which is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, and particularly preferably 200 or less per 50 g of recycled polycarbonate resin particles. If the number is within the above range, the transparency and appearance of the molded plate obtained using the recycled polycarbonate resin particles are good. Furthermore, the lower limit of the number of foreign matters is not particularly limited, but is preferably 5 or more, 10 or more, 20 or more, 30 or more, or 40 or more.

[0147] The number of foreign matters in the present invention was measured by dissolving 50 g of the obtained recycled polycarbonate resin particles in dichloromethane, filtering the solution through a nylon mesh cloth with a mesh size of 20 μm, and then capturing and counting the number of foreign matters remaining on the nylon mesh cloth using an EDS (X-MaxN20 manufactured by Oxford Instruments) and an SEM (SU3900 manufactured by Hitachi High-Technologies) equipped with analysis software (AZtec manufactured by Oxford Instruments).

[0148] The recycled polycarbonate resin particles of the present invention can be used by blending with virgin polycarbonate resin within a range that does not impair the properties of the present invention, and can be used by blending 5 to 100% by weight, 10 to 100% by weight, 20 to 100% by weight, 30 to 100% by weight, 40 to 100% by weight, or 50 to 100% by weight of recycled polycarbonate resin particles with 0 to 95% by weight, 0 to 90% by weight, 0 to 80% by weight, 0 to 70% by weight, 0 to 60% by weight, or 0 to 50% by weight of virgin polycarbonate resin.

[0149] The recycled polycarbonate resin particles of the present invention may further contain, as appropriate, modifiers such as heat stabilizers, antioxidants, release agents (fatty acid esters, etc.), weathering agents (ultraviolet absorbers), nucleating agents, lubricants, plasticizers, antistatic agents, thickeners, antibacterial agents, colorants (pigments, dyes), fillers, reinforcing agents, polymers such as other resins and rubbers, and flame retardants, within the range that does not impair the properties of the present invention. The blending amounts thereof are the same as the ranges of the content of additives in the recycled polycarbonate resin (raw material) described above.

[0150] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples as long as the gist of the invention is not exceeded. <Aspect 1> The physical properties of the examples and comparative examples were evaluated according to the following methods.

[0151] <Average Long Diameter> Using a stereomicroscope (Nikon Solutions, Model: SMZ1270I), a micrograph of the raw recycled polycarbonate resin or its pulverized product was taken, and the long diameter of the particles was measured. With reference to "Materials," Vol. 19, No. 199, Measurement of Fundamental Properties of Powder Materials (I) (Particle Counting Coefficient) (Shigeo Miwa), the long diameter was measured as the maximum distance between two parallel lines tangent to the outline of the plan view of the particle. The long diameter of 50 randomly selected particles was measured, and the average long diameter was calculated.

[0152] <Average particle size> In accordance with JIS Z 8815:1994, general rules for sieving test methods, recycled polycarbonate resin or a pulverized product thereof was sieved using sieves with mesh sizes of 4.75 mm, 2.00 mm, 3.35 mm, 1.40 mm, 1.00 mm, 710 μm, 500 μm, 300 μm, 212 μm, 180 μm, and 106 μm, and then a particle size distribution graph of the cumulative undersieve percentage based on weight was created, and the particle size at which the cumulative weight was 50% was determined and defined as the average particle size.

[0153] <Weight Average Molecular Weight (Mw), Number Average Molecular Weight (Mn), Molecular Weight Distribution (Mw / Mn)> The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were measured using GPC according to the following method. 10 mg of the obtained recycled polycarbonate resin particles were dissolved in 5 ml of chloroform, and 5 μl of the solution was introduced into a GPC apparatus under the following conditions for measurement. Using the above measurement method, the weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated in terms of polystyrene, and the molecular weight distribution (Mw / Mn) was determined. (Measurement Conditions) Apparatus: GPC system (HLC-8420GPC) manufactured by Tosoh Corporation Detector: CH-2 (UV) Column: TSKgel super HZM-M Flow rate: 0.35 mL / min Column temperature: 40.0°C Standard substance: TSK standard polystyrene Eluent: chloroform

[0154] <Oligomer Amount> The oligomer amount was measured using GPC by the following method. 50 mg of the obtained recycled polycarbonate resin particles were dissolved in 5 mL of chloroform, and 20 μl of the solution was introduced into a GPC apparatus under the following conditions for measurement. The ratio (%) of the peak area of ​​oligomer components (number average molecular weight in polystyrene equivalent of less than 6,000) observed at retention times of 7.5 minutes or later in the GPC chart obtained by the above measurement method to the total peak area was determined and calculated as area %. (Measurement Conditions) Apparatus: GPC system (Waters 2695) manufactured by Waters Corporation Column: TSKgel Super H3000 manufactured by Tosoh Corporation Flow rate: 0.6 mL / min Detector: Waters 2487 manufactured by Tosoh Corporation Detection conditions: UV 254 nm Column temperature: 40.0°C Standard substance: TSK standard polystyrene Eluent: Chloroform

[0155] <Amount of additives> The obtained recycled polycarbonate resin particles were dissolved in dichloromethane, and then low molecular weight components were extracted by poor solvent precipitation using hexane. Then, the extract was analyzed using JMN-ECZ400S manufactured by JEOL Ltd. １H-NMR spectra were measured, and the amount of each additive (ultraviolet absorber, release agent, heat stabilizer, colorant) was calculated from the integrated value of the peak derived from each additive. For the ultraviolet absorber, the content and total amount of each compound were calculated for the following three types of benzotriazole-based ultraviolet absorbers detected. For the release agent, heat stabilizer, and colorant, the content of each additive type was calculated. UVA1: 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (molecular weight: 323.44) UVA2: 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (molecular weight: 447.58) UVA3: 2-t-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (molecular weight: 315.80)

[0156] <Number of foreign matters> 50 g of the obtained recycled polycarbonate resin particles were dissolved in dichloromethane and filtered through a nylon mesh cloth with a mesh size of 20 μm. The number of foreign matters remaining on the nylon mesh cloth was counted by capturing an image using an SEM (SU3900 manufactured by Hitachi High-Tech) equipped with an EDS (X-MaxN20 manufactured by Oxford Instruments) and analysis software (AZtec manufactured by Oxford Instruments).

[0157] <Optical Properties> The obtained recycled polycarbonate resin particles were placed in a small twin-screw kneader (Model MC15HT, manufactured by Xplore Instruments), kneaded for 2 minutes at a barrel temperature of 270°C and a screw rotation speed of 100 rpm, and molded in an attached injection molding machine (Model IM12, manufactured by Xplore Instruments) at a cylinder temperature of 270°C and a mold temperature of 80°C to obtain a molded plate with a thickness of 2 mm. Using the obtained molded plate, the total light transmittance (TT), haze, L*, a*, and b* were measured using a color and turbidity simultaneous analyzer COH 400 (D65 light source, 10° field of view) manufactured by Nippon Denshoku Industries Co., Ltd.

[0158] <Charpy Impact Strength> The obtained recycled polycarbonate resin particles were placed in a small twin-screw kneader (Model MC15HT, manufactured by Xplore Instruments) and kneaded for 2 minutes at a barrel temperature of 270°C and a screw rotation speed of 100 rpm, and then molded in an attached injection molding machine (Model IM12, manufactured by Xplore Instruments) at a cylinder temperature of 270°C and a mold temperature of 80°C to obtain a bending test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm. Using the obtained bending test piece, the notched Charpy impact strength was measured in accordance with ISO 179.

[0159] [Example A-1] 200 g of recycled polycarbonate resin pellets MT01300 (average major axis: 4074 μm, average particle size: 2.68 mm) manufactured by Matta (Xiamen) Technology Co., Ltd. and 800 mL of acetone were charged into a 2 L flask and stirred at 40° C. for 1 hour. The acetone was then removed by filtration, and the mixture was dried at 120° C. to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0160] [Examples A-2 to A-4] Recycled polycarbonate resin particles were obtained in the same manner as in Example A-1, except that the contact time of the solvent extraction was carried out for the time shown in Table 1. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0161] [Example A-5] 200 g of the pulverized product (average major axis: 1905 μm, average particle size: 1.75 mm) obtained by pulverizing recycled polycarbonate resin pellets MT01300 manufactured by Matta (Xiamen) Technology Co., Ltd. using a cutter mill in a 25°C environment and 800 mL of acetone were charged into a 2 L flask and stirred at 40°C for 1 hour, after which the acetone was removed by filtration and dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0162] [Examples A-6 to A-8] Recycled polycarbonate resin particles were obtained in the same manner as in Example 5, except that the contact time of the solvent extraction was carried out for the time shown in Table 1. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0163] [Comparative Example A-1] Using recycled polycarbonate resin pellets MT01300 (average major axis: 4074 μm, average particle size: 2.68 mm) manufactured by Matta (Xiamen) Technology, the molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0164] [Comparative Example A-2] 150 g of recycled polycarbonate resin pellets MT01300 (average major axis: 4074 μm, average particle size: 2.68 mm) manufactured by Matta (Xiamen) Technology Co., Ltd. was dissolved in 1350 g of methylene chloride and filtered through a 1 μm filter. The filtered polycarbonate resin solution and an alkaline aqueous solution (900 g of purified water, 11.3 g of NaOH) were charged into a 5 L flask, stirred, and the organic phase was recovered after separation. The recovered polycarbonate resin solution was washed with 900 g of purified water, and the organic phase was recovered after separation. This operation was repeated twice until the aqueous phase became neutral. The water-washed polycarbonate resin solution and acid (900 g of purified water, 12.66 g of concentrated hydrochloric acid (35-37%)) were charged into a 5 L flask, stirred, and the organic phase was recovered after separation. The recovered polycarbonate resin solution was washed with 900 g of pure water, and after separation, the organic phase was recovered. This procedure was repeated twice until the electrical conductivity of the aqueous phase reached 10 μS / cm or less. The resulting polycarbonate resin solution was poured into hot water at 80°C to remove methylene chloride, and the resulting solution was crushed and dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength of the resulting recycled polycarbonate resin particles were evaluated.

[0165] [Example A-9] 200 g of recycled polycarbonate resin pellets PC-116A (average major axis: 3723 μm, average particle size: 2.67 mm) manufactured by Asahi Kogyo Co., Ltd. and 800 mL of acetone were charged into a 2 L flask and stirred at 40° C. for 6 hours. The acetone was then removed by filtration, and the mixture was dried at 120° C. to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0166] [Example A-10] 200 g of recycled polycarbonate resin pellets PC-116A (average major axis: 3723 μm, average particle size: 2.67 mm) manufactured by Asahi Kogyo Co., Ltd. and 800 mL of acetone were charged into a 2 L flask, stirred at 40°C for 6 hours, the acetone was removed by filtration, and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles. 150 g of the obtained recycled polycarbonate resin particles after solvent extraction was dissolved in 1350 g of methylene chloride and filtered through a filter with a mesh size of 1 μm. The filtered polycarbonate resin solution was poured into hot water at 80°C to remove the methylene chloride, pulverized, and then dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0167] [Example A-11] 200 g of pulverized product (average major axis: 2082 μm, average particle size: 1.82 mm) obtained by pulverizing recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kogyo Co., Ltd. using a cutter mill in an environment of 25°C and 800 mL of acetone were charged into a 2 L flask and stirred at 40°C for 6 hours, after which the acetone was removed by filtration and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0168] [Example A-12] 200 g of pulverized product (average major axis: 2082 μm, average particle size: 1.82 mm) obtained by pulverizing recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kogyo Co., Ltd. using a cutter mill in a 25°C environment and 800 mL of acetone were charged into a 2 L flask, stirred at 40°C for 6 hours, filtered to remove the acetone, and dried at 120°C to obtain recycled polycarbonate resin particles. 150 g of the obtained recycled polycarbonate resin particles after solvent extraction was dissolved in 1350 g of methylene chloride and filtered through a filter with a mesh size of 1 μm. The filtered polycarbonate resin solution was poured into hot water at 80°C to remove the methylene chloride, pulverized, and then dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0169] [Example A-13] Recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kouyu Corporation were pulverized in a cutter mill in an environment of 25°C, and 200 g of the pulverized product (average major axis: 2082 μm, average particle size: 1.82 mm) and 800 mL of acetone were charged into a 2-L flask, stirred at 40°C for 6 hours, and then the acetone was removed by filtration. The mixture was dried at 120°C to obtain recycled polycarbonate resin particles.

[0170] 150 g of the resulting recycled polycarbonate resin particles after solvent extraction was dissolved in 1,350 g of methylene chloride and filtered through a 1 μm filter. The filtered polycarbonate resin solution and an alkaline aqueous solution (900 g of pure water, 11.3 g of NaOH) were placed in a 5 L flask, stirred, and separated, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 900 g of pure water, separated, and the organic phase was recovered. This procedure was repeated twice until the aqueous phase became neutral. The water-washed polycarbonate resin solution and acid (900 g of pure water, 12.66 g of concentrated hydrochloric acid (35-37%)) were placed in a 5 L flask, stirred, separated, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 900 g of pure water, separated, and the organic phase was recovered. This procedure was repeated twice until the electrical conductivity of the aqueous phase reached 10 μS / cm or less. The obtained polycarbonate resin solution was poured into hot water at 80°C to remove methylene chloride, and then pulverized and dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0171] [Example A-14] 200 g of pulverized product (average major axis: 353 μm, average particle size: 0.41 mm) obtained by freeze-pulverizing recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kogyo Co., Ltd. and 800 mL of acetone were charged into a 2 L flask and stirred at 40° C. for 6 hours. After the acetone was removed by filtration, the mixture was dried at 120° C. to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0172] Example A-15: 200 g of pulverized product (average major axis: 353 μm, average particle size: 0.41 mm) obtained by freeze-pulverizing recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kogyo Co., Ltd. and 800 mL of acetone were charged into a 2 L flask, stirred at 40°C for 6 hours, filtered to remove the acetone, and dried at 120°C to obtain recycled polycarbonate resin particles. 150 g of the obtained recycled polycarbonate resin particles after solvent extraction was dissolved in 1350 g of methylene chloride and filtered through a filter with a mesh size of 1 μm. The filtered polycarbonate resin solution was poured into hot water at 80°C to remove the methylene chloride, pulverized, and then dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0173] [Example A-16] 200 g of a pulverized product (average major axis: 353 μm, average particle size: 0.41 mm) obtained by freeze-pulverizing recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kogyo Co., Ltd. and 800 mL of acetone were charged into a 2 L flask and stirred at 40°C for 6 hours. After the acetone was removed by filtration, the mixture was dried at 120°C to obtain recycled polycarbonate resin particles.

[0174] 150 g of the resulting recycled polycarbonate resin particles after solvent extraction was dissolved in 1,350 g of methylene chloride and filtered through a 1 μm filter. The filtered polycarbonate resin solution and an alkaline aqueous solution (900 g of pure water, 11.3 g of NaOH) were placed in a 5 L flask, stirred, and separated, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 900 g of pure water, separated, and the organic phase was recovered. This procedure was repeated twice until the aqueous phase became neutral. The water-washed polycarbonate resin solution and acid (900 g of pure water, 12.66 g of concentrated hydrochloric acid (35-37%)) were placed in a 5 L flask, stirred, separated, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 900 g of pure water, separated, and the organic phase was recovered. This procedure was repeated twice until the electrical conductivity of the aqueous phase reached 10 μS / cm or less. The obtained polycarbonate resin solution was poured into hot water at 80°C to remove methylene chloride, and then pulverized and dried at 120°C to obtain recycled polycarbonate resin particles. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0175] [Comparative Example A-3] Using recycled polycarbonate resin pellets PC-116A (average major axis: 3723 μm, average particle size: 2.67 mm) manufactured by Asahi Kogyo Co., Ltd., the molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0176] [Example A-17] Recycled polycarbonate resin particles were obtained in the same manner as in Example A-11, except that propyl acetate was used instead of acetone. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0177] [Example A-18] Recycled polycarbonate resin particles were obtained in the same manner as in Example A-11, except that methanol was used instead of acetone. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0178] [Comparative Example A-4] Recycled polycarbonate resin particles were obtained in the same manner as in Example A-11, except that hexane was used instead of acetone. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0179] Example A-19 Recycled polycarbonate resin particles were obtained in the same manner as in Example A-14, except that pulverized products (average major axis: 273 μm, average particle size: 0.26 mm) obtained by freeze-pulverizing recycled polycarbonate resin pellets PC-T103 manufactured by Ningbo Topcentral New Material Co., Ltd. were used. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0180] Example A-20 Recycled polycarbonate resin particles were obtained in the same manner as in Example A-15, except that pulverized products (average major axis: 273 μm, average particle size: 0.26 mm) obtained by freeze-pulverizing recycled polycarbonate resin pellets PC-T103 manufactured by Ningbo Topcentral New Material Co., Ltd. were used. The molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0181] [Comparative Example A-5] Using a pulverized product (average major axis: 273 μm, average particle size: 0.26 mm) obtained by freeze-pulverizing recycled polycarbonate resin pellets PC-T103 manufactured by Ningbo Topcentral New Material Co., Ltd., the molecular weight distribution, amount of oligomers, amount of additives, number of foreign matters, optical properties, and Charpy impact strength were evaluated.

[0182] Reference Example A-1 Using virgin polycarbonate resin pellets (Panlite L-1225Z100M) manufactured by Teijin, the molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0183] Reference Example A-2 Using virgin polycarbonate resin powder (Panlite L-1225WS) manufactured by Teijin, the molecular weight distribution, oligomer amount, additive amount, number of foreign matters, optical properties, and Charpy impact strength were evaluated.

[0184]

[0185]

[0186]

[0187]

[0188] As is clear from a comparison of Tables 1 and 2 above, the recycled polycarbonate resin particles of the present invention, which have a low content of low-molecular-weight components and a specific molecular weight distribution, significantly improve the impact resistance that has been a problem with recycled polycarbonate resins. The recycled polycarbonate resin particles that have been subjected to solvent extraction have increased b* and L* values ​​after molding, but this is due to the removal of colorants by solvent extraction. When producing a polycarbonate resin composition using the resulting recycled polycarbonate resin particles, the color can be adjusted by adding an appropriate colorant, just as when using virgin polycarbonate resin. It can also be seen that heat resistance (molded color) and transparency are further improved by reducing foreign matter and impurities through filtration and washing processes.

[0189] <Aspect 2> The physical properties of the examples and comparative examples were evaluated according to the following methods.

[0190] <Specific Surface Area> The specific surface area was measured by the BET method using a specific surface area measuring device (GEMINI 2360 manufactured by Micromeritics Co., Ltd.) and nitrogen as the adsorption gas.

[0191] <Bulk Density> Measured in accordance with JIS K 7365.

[0192] <Weight Average Molecular Weight (Mw), Number Average Molecular Weight (Mn), Molecular Weight Distribution (Mw / Mn)> The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were measured using GPC according to the following method. 10 mg of the obtained recycled polycarbonate resin particles were dissolved in 5 ml of chloroform, and 5 μl of the solution was introduced into a GPC apparatus under the following conditions for measurement. Using the above measurement method, the weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated in terms of polystyrene, and the molecular weight distribution (Mw / Mn) was determined. (Measurement Conditions) Apparatus: GPC system (HLC-8420GPC) manufactured by Tosoh Corporation Detector: CH-2 (UV) Column: TSKgel super HZM-M Flow rate: 0.35 mL / min Column temperature: 40.0°C Standard substance: TSK standard polystyrene Eluent: Chloroform

[0193] <Oligomer Amount> The oligomer amount was measured using GPC by the following method. 50 mg of the obtained recycled polycarbonate resin particles were dissolved in 5 mL of chloroform, and 20 μl of the solution was introduced into a GPC apparatus under the following conditions for measurement. The ratio (%) of the peak area of ​​oligomer components (number average molecular weight in polystyrene equivalent of less than 6,000) observed at retention times of 7.5 minutes or later in the GPC chart obtained by the above measurement method to the total peak area was determined and calculated as area %. (Measurement Conditions) Apparatus: GPC system (Waters 2695) manufactured by Waters Corporation Column: TSKgel Super H3000 manufactured by Tosoh Corporation Flow rate: 0.6 mL / min Detector: Waters 2487 manufactured by Tosoh Corporation Detection conditions: UV 254 nm Column temperature: 40.0°C Standard substance: TSK standard polystyrene Eluent: Chloroform

[0194] <Amount of additives> The obtained recycled polycarbonate resin particles were dissolved in dichloromethane, and then low molecular weight components were extracted by poor solvent precipitation using hexane. Then, the extract was analyzed using JMN-ECZ400S manufactured by JEOL Ltd. １H-NMR spectra were measured, and the amount of each additive (ultraviolet absorber, release agent, heat stabilizer, colorant) was calculated from the integrated value of the peak derived from each additive. For the ultraviolet absorber, the content and total amount of each compound were calculated for the following three types of benzotriazole-based ultraviolet absorbers detected. For the release agent, heat stabilizer, and colorant, the content of each additive type was calculated. UVA1: 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (molecular weight: 323.44) UVA2: 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (molecular weight: 447.58) UVA3: 2-t-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (molecular weight: 315.80)

[0195] <Number of foreign matters> 50 g of the obtained recycled polycarbonate resin particles were dissolved in dichloromethane and filtered through a nylon mesh cloth with a mesh size of 20 μm. The number of foreign matters remaining on the nylon mesh cloth was counted by capturing an image using an SEM (SU3900 manufactured by Hitachi High-Tech) equipped with an EDS (X-MaxN20 manufactured by Oxford Instruments) and analysis software (AZtec manufactured by Oxford Instruments).

[0196] <Optical Properties> The obtained recycled polycarbonate resin particles were placed in a small twin-screw kneader (Model MC15HT, manufactured by Xplore Instruments), kneaded for 2 minutes at a barrel temperature of 270°C and a screw rotation speed of 100 rpm, and molded in an attached injection molding machine (Model IM12, manufactured by Xplore Instruments) at a cylinder temperature of 270°C and a mold temperature of 80°C to obtain a molded plate with a thickness of 2 mm. Using the obtained molded plate, the total light transmittance (TT), haze, L*, a*, and b* were measured using a color and turbidity simultaneous analyzer COH 400 (D65 light source, 10° field of view) manufactured by Nippon Denshoku Industries Co., Ltd.

[0197] <Charpy Impact Strength> The obtained recycled polycarbonate resin particles were placed in a small twin-screw kneader (Model MC15HT, manufactured by Xplore Instruments) and kneaded for 2 minutes at a barrel temperature of 270°C and a screw rotation speed of 100 rpm, and then molded in an attached injection molding machine (Model IM12, manufactured by Xplore Instruments) at a cylinder temperature of 270°C and a mold temperature of 80°C to obtain a bending test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm. Using the obtained bending test piece, the notched Charpy impact strength was measured in accordance with ISO 179.

[0198] [Example B-1] A reactor equipped with a stirrer and reflux condenser was charged with recycled polycarbonate resin pellets MT01300 (5 kg) manufactured by Matta (Xiamen) Technology Co., Ltd. and methylene chloride (45 kg), and stirred and dissolved at room temperature. An alkaline aqueous solution (30 kg of purified water, 377 g of NaOH) was then charged, followed by stirring and separation, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 30 kg of purified water, and the organic phase was recovered after separation. This operation was repeated twice until the aqueous phase became neutral. The water-washed polycarbonate resin solution and acid (30 kg of purified water, 422 g of concentrated hydrochloric acid (35-37%)) were charged, stirred, and the organic phase was recovered after separation. The recovered polycarbonate resin solution was washed with 30 kg of pure water, and after separation, the organic phase was recovered. This procedure was repeated twice until the electrical conductivity of the aqueous phase reached 10 μS / cm or less. The solution was passed through a filter with a mesh size of 1 μm and placed in a kneader filled with warm water at 80°C. The methylene chloride was evaporated while stirring and pulverizing, and the mixture was dried at 120°C to obtain a recycled polycarbonate resin powder. The resulting recycled polycarbonate resin powder had a specific surface area of ​​0.12 m. ２ / g, bulk density 0.60 g / cm ３ It was.

[0199] 200 g of the obtained recycled polycarbonate resin powder and 800 mL of acetone were placed in a 2 L flask and stirred at 40° C. for 1 hour, after which the acetone was removed by filtration and the mixture was dried at 120° C. to obtain recycled polycarbonate resin particles. The specific surface area, bulk density, molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the recycled polycarbonate resin particles were evaluated.

[0200] [Examples B-2 to B-4] Recycled polycarbonate resin particles were obtained in the same manner as in Example B-1, except that the contact time of the solvent extraction was carried out for the time shown in Table 3. The specific surface area, bulk density, molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0201] [Example B-5] A reactor equipped with a stirrer and a reflux condenser was charged with recycled polycarbonate resin pellets MT01300 (5 kg) manufactured by Matta (Xiamen) Technology Co., Ltd. and methylene chloride (45 kg), and stirred and dissolved at room temperature. An alkaline aqueous solution (30 kg of purified water, 377 g of NaOH) was then charged, followed by stirring and separation, and the organic phase was recovered. 30 kg of purified water was added to the recovered polycarbonate resin solution, followed by water washing, separation, and recovery of the organic phase. This operation was repeated twice until the aqueous phase became neutral. The water-washed polycarbonate resin solution and acid (30 kg of purified water, 422 g of concentrated hydrochloric acid (35-37%)) were charged, stirred, separated, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 30 kg of pure water, and after separation, the organic phase was recovered. This procedure was repeated twice until the electrical conductivity of the aqueous phase reached 10 μS / cm or less. The solution was passed through a filter with a mesh size of 1 μm and placed in a kneader filled with warm water at 70°C. The methylene chloride was evaporated while stirring and pulverizing, and the mixture was dried at 120°C to obtain a recycled polycarbonate resin powder. The resulting recycled polycarbonate resin powder had a specific surface area of ​​0.06 m. ２ / g, bulk density 0.72 g / cm ３ It was.

[0202] 200 g of the obtained recycled polycarbonate resin powder and 800 mL of acetone were placed in a 2 L flask and stirred at 40° C. for 1 hour, after which the acetone was removed by filtration and the mixture was dried at 120° C. to obtain recycled polycarbonate resin particles. The specific surface area, bulk density, molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the recycled polycarbonate resin particles were evaluated.

[0203] [Comparative Example B-1] In the same manner as in Example B-1, a specific surface area of ​​0.12 m ２ / g, bulk density 0.60 g / cm ３ The recycled polycarbonate resin powder thus obtained was evaluated for its molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0204] [Comparative Example B-2] Recycled polycarbonate resin pellets MT01300 (bulk density: 0.68 g / cm 3 ) manufactured by Matta (Xiamen) Technology Co., Ltd. ３ ) were used to evaluate the molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength. ２ / g) or less, so measurement was not possible.

[0205] [Example B-6] Recycled polycarbonate resin pellets MT01300 (250 g) manufactured by Matta (Xiamen) Technology Co., Ltd. were dissolved in 2250 g of methylene chloride and filtered through a filter with a mesh size of 1 μm. The filtered polycarbonate resin solution was poured into hot water at 80°C to remove the methylene chloride, and the mixture was wet-pulverized in a mixer and dried at 120°C to obtain a recycled polycarbonate resin powder. The resulting recycled polycarbonate resin powder had a specific surface area of ​​0.34 m ２ / g, bulk density 0.44 g / cm ３200 g of the obtained recycled polycarbonate resin powder and 800 mL of acetone were charged into a 2 L flask and stirred at 40°C for 1 hour, after which the acetone was removed by filtration and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles. The specific surface area, bulk density, molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the recycled polycarbonate resin particles were evaluated.

[0206] [Examples B-7 to B-9] Recycled polycarbonate resin particles were obtained in the same manner as in Example B-6, except that the contact time of the solvent extraction was carried out for the time shown in Table 3. The specific surface area, bulk density, molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the recycled polycarbonate resin particles were evaluated.

[0207] [Comparative Example B-3] In the same manner as in Example B-6, a specific surface area of ​​0.34 m ２ / g, bulk density 0.44 g / cm ３ The recycled polycarbonate resin powder thus obtained was evaluated for its molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0208] [Comparative Example B-4] Recycled polycarbonate resin pellets MT01300 (bulk density: 0.68 g / cm 3 ) manufactured by Matta (Xiamen) Technology Co., Ltd. ３ 200 g of cellulose acetate and 800 mL of acetone were placed in a 2-L flask and stirred at 40°C for 1 hour. The acetone was then removed by filtration, and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for bulk density, molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength. The specific surface area was measured at the lower limit of measurement (<0.01 m). ２ / g) or less, so measurement was not possible.

[0209] Comparative Example B-5 Recycled polycarbonate resin particles were obtained in the same manner as in Comparative Example B-4, except that the contact time of the solvent extraction was carried out for the time shown in Table 3. The bulk density, molecular weight distribution, oligomer amount, additive amount, foreign matter count, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated. The specific surface area was measured at the lower limit of measurement (<0.01 m). ２ / g) or less, so measurement was not possible.

[0210] [Comparative Example B-6] A pulverized product (specific surface area 0.03 m) obtained by pulverizing recycled polycarbonate resin pellets MT01300 manufactured by Matta (Xiamen) Technology Co., Ltd. in a cutter mill at 25°C. ２ / g, bulk density 0.55 g / cm ３ 200 g of the above-mentioned cellulose acetate copolymer and 800 mL of acetone were placed in a 2-L flask and stirred at 40° C. for 1 hour. The acetone was then removed by filtration, and the mixture was dried at 120° C. to obtain recycled polycarbonate resin particles. The specific surface area, bulk density, molecular weight distribution, amount of oligomers, amount of additives, number of foreign matters, optical properties, and Charpy impact strength of the obtained recycled polycarbonate resin particles were evaluated.

[0211]

[0212]

[0213]

[0214] As is clear from a comparison of Tables 3 and 4 above, the recycled polycarbonate resin particles of the present invention, which have a low content of low-molecular-weight components and a specific molecular weight distribution and specific surface area, significantly improve the impact resistance that has been a problem with recycled polycarbonate resins. The recycled polycarbonate resin particles that have been subjected to solvent extraction have increased b* and L* values ​​after molding, but this is due to the removal of coloring agents by solvent extraction. When producing a polycarbonate resin composition using the resulting recycled polycarbonate resin particles, the color can be adjusted by adding an appropriate coloring agent, just as when using virgin polycarbonate resin. It can also be seen that heat resistance (hue after molding) and transparency are further improved by reducing foreign matter and impurities through filtration and washing processes.

[0215] The recycled polycarbonate resin particles of the present invention, which have a low content of low-molecular-weight components and a specific molecular weight distribution or a specific molecular weight distribution and specific surface area, can significantly improve the impact resistance that has been a problem with recycled polycarbonate resins, and further, by reducing foreign matter and impurities, can be widely used as a recycled material that has excellent heat resistance (color after molding) and transparency, and is suitable for use in the wide variety of applications in which virgin polycarbonate resins are used.

Claims

Recycled polycarbonate resin particles characterized in that the amount of oligomers determined by gel permeation chromatography (GPC) is 1.4% or less and the molecular weight distribution (Mw / Mn) is 2.3 or less.

2. The recycled polycarbonate resin particles according to claim 1, wherein the total amount of benzotriazole-based ultraviolet absorbers having a molecular weight of 1,000 or less is 1,000 ppm or less.

2. The recycled polycarbonate resin particles according to claim 1, wherein the number of foreign matters insoluble in methylene chloride collected through a nylon mesh having an opening of 20 μm is 1,500 or less per 50 g of the recycled polycarbonate resin particles. 　 Recycled polycarbonate resin particles with an average major axis of 200 to 5000 μm and a solubility parameter of 16 to 30 MPa ０．５ 4. The method for producing recycled polycarbonate resin particles according to claim 1, wherein the organic solvent is contacted with the polycarbonate resin particles for 10 minutes to 7 hours. 　 A method for producing recycled polycarbonate resin particles, comprising dissolving the recycled polycarbonate resin particles obtained by the method according to claim 4 in a halogenated hydrocarbon solvent, filtering the recycled polycarbonate resin solution, and then removing the halogenated hydrocarbon solvent to produce recycled polycarbonate resin particles.

5. A method for producing recycled polycarbonate resin particles, comprising dissolving the recycled polycarbonate resin particles obtained by the production method according to claim 4 in a halogenated hydrocarbon solvent, subjecting the polycarbonate resin solution to one or more treatments selected from the group consisting of water washing, acid washing and alkali washing before and / or after filtering the recycled polycarbonate resin solution, and then removing the halogenated hydrocarbon solvent to produce recycled polycarbonate resin particles. 　 The oligomer content determined by gel permeation chromatography (GPC) is 0.8% or less, the molecular weight distribution (Mw / Mn) is 2.3 or less, and the specific surface area measured by gas adsorption method is 0.05 to 1.2 g / cm ３ Recycled polycarbonate resin particles, characterized by:

8. The recycled polycarbonate resin particles according to claim 7, wherein the total amount of benzotriazole-based ultraviolet absorbers having a molecular weight of 1,000 or less is 500 ppm or less.

8. The recycled polycarbonate resin particles according to claim 7, wherein the number of foreign matter particles insoluble in methylene chloride collected through a nylon mesh with an opening of 20 μm is 500 or less per 50 g of the recycled polycarbonate resin particles. The recycled polycarbonate resin is dissolved in a halogenated hydrocarbon solvent, the recycled polycarbonate resin solution is filtered, the halogenated hydrocarbon solvent is removed, and the specific surface area measured by the gas adsorption method is 0.06 to 1.5 g / cm ３ The recycled polycarbonate resin powder is produced, and the resulting recycled polycarbonate resin powder and a solubility parameter of 16 to 30 MPa are mixed. ０．５ 10. The method for producing recycled polycarbonate resin particles according to claim 7, wherein the organic solvent is contacted with the polycarbonate resin particles for 5 minutes to 6 hours.

11. The method for producing recycled polycarbonate resin particles according to claim 10, wherein the polycarbonate resin solution is subjected to one or more treatments selected from the group consisting of water washing, acid washing, and alkali washing before and / or after filtering the recycled polycarbonate resin solution.

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