Recycled polycarbonate resin particles and process for producing the same

Abstract

To provide recycled polycarbonate resin particles excellent in impact resistance, heat resistance (hue after molding) and transparency.SOLUTION: The recycled polycarbonate resin particles have an oligomer content of ≤1.4% as determined by gel permeation chromatography (GPC) and a molecular weight distribution (Mw / Mn) of ≤2.3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to recycled polycarbonate resin particles, and more particularly 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. [Background technology]

[0002] Plastic materials are used in a wide range of applications, taking advantage of their characteristics such as impact resistance, light weight, and ease of processing. In most cases, current industrial production methods do not produce plastic materials as substances with a single molecular weight, but as mixtures with a molecular weight distribution. Of these, low molecular weight components degrade the physical properties of plastic materials, so it is desirable that the content be low.

[0003] In addition, plastic materials are used with various additives to improve weather resistance, flame retardancy, and design. However, these additives and their modifications are often low-molecular-weight components, which can impair physical properties, so the amount added must be properly controlled before use.

[0004] In recent years, in response to resource depletion and growing awareness of environmental protection, recycling, in which plastic materials are recovered and remolded after use, has become increasingly common.

[0005] With regard to recovered plastic materials, there is a strong need to remove low molecular weight substances because the resin deteriorates (decomposes) during the manufacturing (molding) and use processes, and various additives are added, resulting in a large amount of low molecular weight substances compared to virgin resin.

[0006] 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.

[0007] 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 investigates 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 no investigation has been made into the low-molecular-weight component ratio and particle size of recycled materials, or the method for achieving them. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 4-306227 Summary of the Invention [Problem to be solved by the invention]

[0009] 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. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have discovered that by using recycled polycarbonate resin particles that have a low content of low molecular weight components and a specific molecular weight distribution, it is possible to provide a recycled material that is excellent in impact resistance, heat resistance (color after molding) and transparency, and have thus completed the present invention.

[0011] That is, according to the present invention, the object of the invention is achieved as follows. 1. 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. Recycled polycarbonate resin particles according to the preceding paragraph 1, in which the total amount of benzotriazole-based ultraviolet absorbers having a molecular weight of 1000 or less is 1000 ppm or less. 3. Recycled polycarbonate resin particles according to the preceding paragraph 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 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 any one of items 1 to 3 above, wherein the organic solvent is contacted with the resin 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 production method described in the preceding paragraph 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. 6. A method for producing recycled polycarbonate resin particles, comprising dissolving the recycled polycarbonate resin particles obtained by the production method described in the preceding paragraph 4 in a halogenated hydrocarbon solvent, subjecting the polycarbonate resin solution to one or more 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. [Effects of the Invention]

[0012] 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, 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. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below.

[0014] <Recycled polycarbonate resin (raw material)> The recycled polycarbonate resin (raw material) that can be used in the present invention refers to injection-molded products containing polycarbonate resin or crushed sprues or runners generated during injection molding, extrusion-molded products such as films or sheets or crushed scraps generated during extrusion molding, and pellets made from these crushed materials in an extruder.Post-consumer recycled (PCR) material, post-industrial recycled (PIR) material, or a combination of these recycled materials may be used.

[0015] 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.

[0016] <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.

[0017] Representative examples of dihydric phenols 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.

[0018] In the present invention, in addition to bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, it is 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 shape stability are particularly strict requirements. These dihydric phenols other than BPA are preferably used in an amount of 5 mol % or more, 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 suitable. (1) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component 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%, and even more preferably 60 to 85 mol%) and BCF accounts for 5 to 90 mol% (more preferably 10 to 50 mol%, and even more preferably 15 to 40 mol%). (3) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component 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 Bis-TMC accounts for 20 to 80 mol% (more preferably 25 to 60 mol%, and even more preferably 35 to 55 mol%).

[0019] 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-6-172508, JP-A-8-27370, JP-A-2001-55435, and JP-A-2002-117580.

[0020] Among the various polycarbonate resins mentioned above, those in which the copolymer composition and the like are adjusted to bring the water absorption rate and Tg (glass transition temperature) into the ranges described below have good hydrolysis resistance of the polymer itself and are remarkably excellent in terms of low warpage after molding, and are therefore particularly suitable in fields where dimensional stability is required. (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 of 0.10 to 0.30%, preferably 0.13 to 0.30%, more preferably 0.14 to 0.27%.

[0021] Here, the water absorption rate of polycarbonate resin is a value measured by using a disk-shaped test piece with a diameter of 45 mm and a thickness of 3.0 mm and immersing it in water at 23°C for 24 hours in accordance with ISO 62-1980, and then measuring the moisture content. Also, Tg (glass transition temperature) is a value determined by differential scanning calorimetry (DSC) measurement in accordance with JIS K7121.

[0022] Carbonate precursors that can be used include carbonyl halides, carbonic acid diesters, and haloformates, and specific examples include phosgene, diphenyl carbonate, and dihaloformates of dihydric phenols.

[0023] When producing a polycarbonate resin by interfacial polymerization of the dihydric phenol and carbonate precursor, 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. A mixture of two or more of the obtained polycarbonate resins may also be used.

[0024] The branched polycarbonate resin can impart anti-drip properties to the thermoplastic resin composition of the present invention. Examples of trifunctional or higher polyfunctional aromatic compounds used in such branched polycarbonate 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- 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.

[0025] In the branched polycarbonate resin, the structural units derived from polyfunctional aromatic compounds are preferably 0.01 to 2.5 mol%, more preferably 0.05 to 1.5 mol%, and even more preferably 0.05 to 1.0 mol%, based on the total 100 mol% of the structural units derived from dihydric phenols and the structural units derived from such polyfunctional aromatic compounds. In particular, in the case of the melt transesterification method, branched structural units may be generated as a side reaction. The amount of such branched structural units is 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%, based on the total 100 mol% of the structural units derived from dihydric phenols. The proportion of such branched structures can be calculated by H-NMR measurement.

[0026] The aliphatic bifunctional carboxylic acid is preferably an α,ω-dicarboxylic acid. Preferred examples of the aliphatic bifunctional 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 bifunctional alcohol is more preferably an alicyclic diol, such as cyclohexanedimethanol, cyclohexanediol, and tricyclodecanedimethanol.

[0027] The reaction modes of the methods 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 a cyclic carbonate compound, are well known in various literatures 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. A polycarbonate resin having a viscosity-average molecular weight of less than 12,500 may not provide good mechanical properties. On the other hand, a resin composition obtained from a polycarbonate resin having a viscosity-average molecular weight of more than 32,000 may have poor moldability.

[0028] The viscosity average molecular weight in the present invention is determined by first calculating the specific viscosity (η SP ) was determined using an Ostwald viscometer from a solution of 0.7 g of polycarbonate dissolved in 100 ml of methylene chloride at 20°C. Specific viscosity (η SP )=(t-t0) / t0 [t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls] The calculated specific viscosity (η SP ) and calculate the viscosity average molecular weight M using the following formula: η 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 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.

[0029] The polycarbonate resin of the present invention may be a polycarbonate-polydiorganosiloxane copolymer resin, 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):

[0030] [ka]

[0031] [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 multiple 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):

[0032] [ka]

[0033] [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 multiple groups, they may be the same or different; g is an integer of 1 to 10, and h is an integer of 4 to 7.

[0034] [ka]

[0035] [In the above general formula (3), R 3 , 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 of 10 to 300. X is a divalent aliphatic group having 2 to 8 carbon atoms.

[0036] 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.

[0037] 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.

[0038] As the hydroxyaryl-terminated polydiorganosiloxane represented by the above general formula (3), for example, the compounds shown below are preferably used.

[0039] [ka]

[0040] Hydroxyaryl-terminated polydiorganosiloxanes (II) can be easily produced by hydrosilylation of phenols having olefinically unsaturated carbon-carbon bonds, preferably vinylphenol, 2-allylphenol, isopropenylphenol, or 2-methoxy-4-allylphenol, at the end of a polysiloxane chain having a predetermined degree of polymerization. Among these, (2-allylphenol)-terminated polydiorganosiloxanes and (2-methoxy-4-allylphenol)-terminated polydiorganosiloxanes are preferred, with (2-allylphenol)-terminated polydimethylsiloxanes and (2-methoxy-4-allylphenol)-terminated polydimethylsiloxanes being particularly preferred. The molecular weight distribution (Mw / Mn) of the hydroxyaryl-terminated polydiorganosiloxanes (II) is preferably 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 upper limit of this preferred range is exceeded, the amount of outgassing during high-temperature molding may be large, and low-temperature impact resistance may be poor.

[0041] Furthermore, in order to achieve high 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.

[0042] The polydiorganosiloxane content of the polycarbonate-polydiorganosiloxane copolymer resin usable in the present invention is preferably 0.1 to 50% by weight based on the total weight. The polydiorganosiloxane component content is more preferably 0.5 to 30% by weight, and even more preferably 1 to 20% by weight. 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 easily achieved. The polydiorganosiloxane polymerization degree and polydiorganosiloxane content can be calculated by 1H-NMR measurement.

[0043] 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 hydroxyaryl-terminated polydiorganosiloxane (II) may be used in combination in an amount of up to 10% by weight based on the total weight of the copolymer, provided that this does not interfere with the present invention.

[0044] 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-forming compound in a mixed solution of a water-insoluble organic solvent and an aqueous alkaline solution.

[0045] In producing an oligomer of the dihydric phenol (I), the entire amount of the dihydric phenol (I) used in the method of the present invention may be converted into an oligomer at once, or a part 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 there is no need to add it if it is not necessary. The method for this oligomer formation reaction is not particularly limited, but it is usually preferable to carry out the reaction in a solvent in the presence of an acid binder.

[0046] The proportion of the carbonate ester-forming compound used may be adjusted appropriately taking into consideration the stoichiometric ratio (equivalents) of the reaction. When a gaseous carbonate ester-forming compound such as phosgene is used, it is preferable to blow it into the reaction system.

[0047] 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).

[0048] The solvent may be any of various inert solvents used in the production of known polycarbonates, either singly 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.

[0049] 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.

[0050] In this way, a mixed solution containing an oligomer of dihydric phenol (I) having terminal chloroformate groups is obtained, and then the mixed solution is stirred while adding 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.

[0051] [ka]

[0052] (In the above general formula (3), R 3 , 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 of 10 to 300. X is a divalent aliphatic group having 2 to 8 carbon atoms.

[0053] When carrying out the interfacial polycondensation reaction, an acid binder may be added as appropriate, taking into account the stoichiometric ratio (equivalents) of the reaction. Examples of acid binders that can be used 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) used, or a portion of the dihydric phenol (I) as described above, is added to this reaction stage as a post-added monomer, 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).

[0054] The polycondensation by interfacial polycondensation reaction between the oligomer of dihydric phenol (I) and the hydroxyaryl-terminated polydiorganosiloxane (II) is carried out by vigorously stirring the mixture.

[0055] In such polymerization reactions, a terminal terminator or a molecular weight modifier is usually used. Examples of terminal terminators 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, and it is of course possible to use two or more compounds in combination.

[0056] To accelerate the polycondensation reaction, a catalyst such as a tertiary amine such as 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.

[0057] 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-hydroxydiphenyl)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 Examples include trisphenols such as {1,1-bis(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, and among these, 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, with 1,1,1-tris(4-hydroxyphenyl)ethane being 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.

[0058] The reaction pressure can be reduced, normal, or increased, but is usually preferably normal pressure or the inherent 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 determined because it varies depending on other conditions such as the reaction temperature, but is usually 0.5 to 10 hours.

[0059] In some cases, the obtained polycarbonate-polydiorganosiloxane copolymer resin is 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 It can also be obtained as a polycarbonate-polydiorganosiloxane copolymer resin of formula [ / c].

[0060] 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).

[0061] 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. This 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.

[0062] 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 using small-angle X-ray scattering (SAXS). Small-angle X-ray scattering measures the diffuse scattering and diffraction that occur in the small-angle region of scattering angles (2θ) less than 10°. In this 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 being measured is determined based on the scattering angle and scattering intensity. In the case of polycarbonate-polydiorganosiloxane copolymer resins, which 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 the particle size distribution, a simulation is performed using commercially available analysis software based on a hypothetical particle size and a 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 in a polycarbonate polymer matrix, which cannot be accurately measured using 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 that normalizes the spread of the 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):

[0063]

number

[0064] <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 the polycarbonate resin, known functional agents such as mold release agents, heat stabilizers, UV absorbers, flow modifiers, and antistatic agents. The main additives that may be contained in the recycled polycarbonate resin (raw material) used as the raw material include the following:

[0065] (i) Mold release agent The recycled polycarbonate resin (raw material) used in the present invention may also contain a release agent, provided that the effects of the present invention are not impaired. Examples of release agents include fatty acid esters, polyolefin waxes (such as polyethylene waxes and 1-alkene polymers, including those modified with functional group-containing compounds such as acid-modified ones), fluorine compounds (such as fluorine oils typified by polyfluoroalkyl ethers), paraffin wax, and beeswax. Among these, fatty acid esters are preferred due to their ease of availability, releasability, and transparency. The 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). A content above the lower limit of the above range clearly improves the release properties of the polycarbonate resin, while a content below the upper limit reduces adverse effects such as mold contamination during molding of the polycarbonate resin.

[0066] Among the above, fatty acid esters, which are preferably used 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 having dihydric or higher hydric groups. The number of carbon atoms in the alcohol is preferably in the range of 3 to 32, more preferably in the range of 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.

[0067] 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. Of these, saturated aliphatic carboxylic acids are particularly preferred. Such aliphatic carboxylic acids are usually produced from natural fats and oils such as animal fats (beef tallow, lard, etc.) and vegetable fats (palm oil, etc.). Therefore, these aliphatic carboxylic acids are usually 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.

[0068] The aforementioned fatty acid esters may be either partial esters or full esters, but partial esters are preferred for 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.

[0069] 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.

[0070] 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 120-150°C and a vacuum of 0.01-0.03 kPa. Furthermore, a centrifugal molecular distillation apparatus is used to obtain high-purity fatty acid partial esters as a distillate at a distillation temperature of 160-230°C and a vacuum of 0.01-0.2 Torr. Sodium metal can be removed as a distillation residue. The resulting distillate can be further purified by repeated molecular distillation, yielding fatty acid partial esters with 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 its airtightness to prevent contamination by sodium metal components from the external environment. Such fatty acid esters are available from specialized suppliers (e.g., Riken Vitamin Co., Ltd.).

[0071] (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 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.

[0072] 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-isopropylphenyl)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.

[0073] Other phosphite compounds that may be used include those that react with dihydric phenols to form a cyclic structure, 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.

[0074] 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.

[0075] Examples of 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 include (2,4-di-tert-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-n-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, and bis(2,6-di-tert-butylphenyl)-3-phenyl-phenylphosphonite. Tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenylphosphonite are preferred, with tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite 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.

[0076] Examples of the phosphonate compound include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.

[0077] 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.

[0078] 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.

[0079] (iii) Hindered phenol stabilizers (antioxidants) The recycled polycarbonate resin (raw material) used in the present invention may contain a hindered phenol stabilizer, the main purpose of which is to improve its thermal stability during molding and heat aging resistance. Examples of such hindered phenol 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, 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'-ethyl butylidene-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], bis[2-t ert-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'-dithiobis(2,6-di-tert-butylphenol), 4,4'-trithiobis(2,6-di-tert-butylphenol), 2,2-thiodiethylene bis-[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 Examples include 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-tris2[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.

[0080] 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 parts 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 it is too much, it may conversely deteriorate the physical properties of the material or cause mold contamination during molding.

[0081] 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).

[0082] (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.

[0083] 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, and the like. Examples include 2-hydroxyphenyl-2H-benzotriazole skeleton-containing polymers such as 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 copolymers of 2-(2'-hydroxy-5-methacryloxyethylphenyl)-2H-benzotriazole and vinyl monomers copolymerizable with the monomers, and copolymers of 2-(2'-hydroxy-5-acryloxyethylphenyl)-2H-benzotriazole and vinyl monomers copolymerizable with the monomers.

[0084] Specific examples of UV absorbers include hydroxyphenyltriazines such as 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.

[0085] Specific examples of cyclic iminoester 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).

[0086] Specific examples of cyanoacrylate 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.

[0087] 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 imino ester skeleton, and a cyanoacrylate skeleton in the ester substituent of a (meth)acrylic acid ester.

[0088] Among the above, benzotriazole-based and hydroxyphenyltriazine-based compounds are preferred in terms of ultraviolet absorbing ability, and cyclic iminoester-based and cyanoacrylate-based compounds are preferred in terms of heat resistance and color. The above ultraviolet absorbents may be used alone or in combination of two or more.

[0089] The ultraviolet 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).

[0090] (v) Flow modifier 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. Such flow modifiers are preferably used in an amount of 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 per 100 parts by weight of polycarbonate resin. Polycaprolactone is particularly preferred, and may be contained in an amount of 2 to 7 parts by weight, particularly preferably, per 100 parts by weight of 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, with 2,500 to 15,000 being particularly preferred.

[0091] (vi) antistatic agent 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 amount of antistatic agent may be 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, relative to 100 parts by weight of recycled polycarbonate resin (raw material). At or above the lower limit, the antistatic effect of the polycarbonate resin can be 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.

[0092] 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 can be appropriately selected and used as long as they do not impair the effects of the present invention.

[0093] The bluing agent may be contained in the recycled polycarbonate resin (raw material) preferably in an amount of 0.05 to 3.0 ppm (weight ratio). Typical examples of the bluing agent include Macrolex Violet B and Macrolex Blue RR from Bayer, and Polythren Blue RLS from Clariant.

[0094] 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).

[0095] Examples of flame retardants include sulfonic acid metal salt flame retardants, halogen-containing compound flame retardants, phosphorus-containing compound flame retardants, and silicon-containing compound flame retardants. Among these, sulfonic acid metal salt flame retardants are preferably used. 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).

[0096] <Method for producing recycled polycarbonate resin particles> <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 eluting 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.

[0097] 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 Japanese Patent Application Laid-Open Nos. 63-278929 and 64-6020, involves placing 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 Japanese Patent Application Laid-Open Nos. 4-306227 and 4-145903, is a production method in which, when extracting impurities from 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, allowing continuous countercurrent contact while the organic solvent is discharged from the top of the extraction vessel. 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. The resulting mixture is then subjected to solid-liquid separation and dried. As reported in Japanese Patent Laid-Open Publication No. 4-306227, the batch process (i) is inefficient for industrial use and has the drawback of generating fine polycarbonate powder due to long stirring times, which impairs the efficiency of solid-liquid separation. Furthermore, it has been confirmed that when acetone used as an organic solvent is repeatedly separated, recovered, and reused, the amount of residual methylene chloride in the dry powder obtained by acetone extraction gradually increases. For these reasons, the continuous process (ii) is preferred for industrial use.

[0098] 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.

[0099] 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. Here, the solubility parameter is 16 to 30 (MPa 0.5 Preferred organic solvents 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 preferred because it can efficiently extract monomers, oligomers, additives, and modified products thereof, and because it has a low boiling point and can be easily separated and recovered by distillation. Furthermore, two or more of these organic solvents can be used in combination, if necessary.

[0100] 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 to effect continuous countercurrent contact, 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 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) = volume of liquid in extraction vessel (m 3 ) / Resin and organic solvent input (=extraction) speed (m 3 / hr)···(2)

[0101] 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 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.

[0102] 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 extractor is preferably equipped with a jacket or a heat-retaining mechanism.

[0103] 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 made from these crushed materials in an extruder. Many of these materials are amorphous and may fuse instantly upon contact with organic solvents. To ensure a 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.

[0104] The recycled polycarbonate resin (raw material) having the above average major axis and average particle size may be produced by a known method including a mechanical pulverization method and a wet method, or a commercially available product may be used.

[0105] In the mechanical pulverization method, for example, 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.

[0106] 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 (roll crushers, etc.), impact pulverizers (impact crushers, hammer mills, etc.), cutting or shear pulverizers (cutter mills, reciprocating pulverizers, low-speed rotary pulverizers (biaxial shear pulverizers, etc.)), impact shear pulverizers (shredders, etc.), and various fine pulverizers (ball mills, disk mills, pin mills, hammer mills, turbo mills, jet mills, etc.). 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 pulverized products with an appropriate bulk density, even for highly tough exterior molded products. Any type of low-speed rotary crusher can be used, such as a single-shaft, double-shaft, or triple-shaft type. In mechanical crushing, frictional heat generated by the recycled polycarbonate resin (raw material) during crushing can 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 crushed.

[0107] According to the mechanical pulverization method, the average major axis and average particle size of the produced particles can be adjusted to the desired range by appropriately adjusting the amount of solvent relative to the recycled polycarbonate resin (raw material), or the pulverization method or speed.

[0108] In the wet method, for example, a dispersion liquid in which recycled polycarbonate resin (raw material) is dispersed with a surfactant or the like is dried to obtain particles having the desired average major axis and average particle diameter.

[0109] The organic solvent is removed from the slurry discharged by the solvent extraction, preferably by filtration, centrifugation or the like, and then the slurry is dried to obtain the recycled polycarbonate resin particles of the present invention.

[0110] The dryer may be 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.

[0111] <Filtration process> To reduce the amount of foreign matter in 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 filtered, and the halogenated hydrocarbon solvent 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. Preferably, the halogenated hydrocarbon solvent is one in which 90% by volume or more of the solvent is a good solvent, and particularly preferably one that is essentially composed of a good solvent.

[0112] 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 contains an appropriate amount of halogenated hydrocarbon solvent, so that subsequent removal of the solvent does not require excessive energy, which is advantageous in terms of economical production.

[0113] 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.

[0114] The recycled polycarbonate resin solution after the filtration treatment is granulated and dried to obtain the recycled polycarbonate resin particles of the present invention. There are no particular restrictions on the granulation and drying methods, and known methods can be used.

[0115] <Cleaning process> 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 of 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.

[0116] The washing process involves dissolving the recycled polycarbonate resin in a halogenated hydrocarbon solvent, mixing and stirring the recycled polycarbonate resin 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, 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 resulting recycled polycarbonate resin has a good color. The washing process may be performed either before or after filtration.

[0117] The recycled polycarbonate resin solution after the washing treatment is granulated and dried to obtain the recycled polycarbonate resin particles of the present invention. There are no particular restrictions on the granulation and drying methods, and known methods can be used.

[0118] <Recycled polycarbonate resin particles> The particle shape of the recycled polycarbonate resin particles of the present invention is not particularly limited, but similarly to the above-mentioned 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.

[0119] <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. A molecular weight distribution within this range is preferable because molded articles obtained from the recycled polycarbonate resin particles have good impact resistance. 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.

[0120] In the present invention, Mw and Mn are 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: Tosoh Corporation GPC system (HLC-8420GPC) Detector: CH-2 (UV) Column: TSKgel superHZM-M Flow rate: 0.35mL / min Column temperature: 40.0℃ Standard material: TSK standard polystyrene Eluent: chloroform

[0121] <Oligomer amount> 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. 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.

[0122] The amount of oligomer in the present invention is calculated as the area % by dissolving 50 mg of a sample in 5 ml of chloroform, introducing 20 μl of the solution into a GPC apparatus under the conditions described below, and determining the ratio (%) of the peak area of ​​oligomer components (number average molecular weight in polystyrene terms of less than 6,000) observed at retention times of 7.5 minutes or later to the total peak area, and the amount includes monomers, oligomers, additives, and modified products thereof. (Measurement conditions) Apparatus: GPC system (Waters 2695) manufactured by Waters Corporation Column: TSKgel SuperH3000 manufactured by Tosoh Corporation Flow rate: 0.6mL / min Detector: Tosoh Corporation Waters2487 Detection conditions: UV254nm Column temperature: 40.0℃ Standard material: TSK standard polystyrene Eluent: Chloroform

[0123] <Additive amount> In the recycled polycarbonate resin particles of the present invention, it is preferable that the residual amounts of various additives are reduced, because this makes it easier to prepare materials suitable for various applications when reusing the recycled polycarbonate resin particles.

[0124] In particular, the recycled polycarbonate resin particles of the present invention preferably contain 1000 ppm or less of benzotriazole-based UV absorbers in total, more preferably 700 ppm or less, even more preferably 500 ppm or less, and particularly preferably 300 ppm or less, in a total amount of benzotriazole-based UV absorbers with a molecular weight of 1000 or less. If a large amount of low-molecular-weight benzotriazole-based UV absorbers or modified products thereof remains, molding defects such as mold contamination and deterioration in the color of molded plates are likely to occur. Furthermore, 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.

[0125] 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.

[0126] 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, in order to easily adjust 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.

[0127] 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.

[0128] 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 3000 ppm or less, more preferably 2500 ppm or less, even more preferably 2000 ppm or less, particularly preferably 1500 ppm or less, and most preferably 1000 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.

[0129] 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 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.

[0130] <Number of foreign objects> The recycled polycarbonate resin particles of the present invention preferably have a methylene chloride-insoluble foreign matter count 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 per 50 g of recycled polycarbonate resin particles when collected through a nylon mesh with a mesh size of 20 μm. Within the above range, the transparency and appearance of molded plates obtained using the recycled polycarbonate resin particles are excellent. The lower limit of the foreign matter count 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.

[0131] The number of foreign particles in the present invention was determined by dissolving 50 g of the obtained recycled polycarbonate resin particles in dichloromethane, filtering through a nylon mesh cloth with 20 μm openings, and then capturing and counting the number of foreign particles remaining on the nylon mesh cloth using an EDS (X-MaxN20 manufactured by Oxford Instruments) and an SEM (SU3900 manufactured by Hitachi High-Tech) equipped with analysis software (AZtec manufactured by Oxford Instruments).

[0132] 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 in ratios of 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.

[0133] 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 range of the content of additives in the recycled polycarbonate resin (raw material) described above. [Example]

[0134] 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. The physical properties of the examples and comparative examples were evaluated according to the following methods.

[0135] <Average length> Using a stereo microscope (Nikon Solutions, Model: SMZ1270i), micrographs of the raw recycled polycarbonate resin or its crushed product were taken, and the long diameter of the particles was measured. Based on "Materials," Vol. 19, No. 199, Measurement of Fundamental Properties of Powder Materials (I) (Particle Weighting Coefficient) (Shigeo Miwa), the long diameter was measured as the maximum distance between two parallel lines tangent to the outline of the particle in a plan view. The long diameter of 50 randomly selected particles was measured, and the average long diameter was calculated.

[0136] <Average particle size> In accordance with JIS Z 8815:1994, General Rules for Sieving Test Methods, recycled polycarbonate resin or its crushed product was sieved using sieves with openings 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. After that, 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 used as the average particle size.

[0137] <Weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn)> Using GPC, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were measured by the following method. 10 mg of the obtained recycled polycarbonate resin particles was dissolved in 5 ml of chloroform, and 5 μl of the solution was introduced into a GPC apparatus under the following conditions for measurement: The weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated in terms of polystyrene using the above measurement method, and the molecular weight distribution (Mw / Mn) was determined. (Measurement conditions) Apparatus: Tosoh Corporation GPC system (HLC-8420GPC) Detector: CH-2 (UV) Column: TSKgel superHZM-M Flow rate: 0.35mL / min Column temperature: 40.0℃ Standard material: TSK standard polystyrene Eluent: chloroform

[0138] <Oligomer amount> The amount of oligomer was measured by the following method using GPC. 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 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 on the GPC chart obtained by the above measurement method was determined as a percentage (%) of the total peak area, and calculated as area %. (Measurement conditions) Apparatus: GPC system (Waters 2695) manufactured by Waters Corporation Column: TSKgel SuperH3000 manufactured by Tosoh Corporation Flow rate: 0.6mL / min Detector: Tosoh Corporation Waters2487 Detection conditions: UV254nm Column temperature: 40.0℃ Standard material: TSK standard polystyrene Eluent: Chloroform

[0139] <Additive amount> The obtained recycled polycarbonate resin particles were dissolved in dichloromethane, and then low molecular weight components were extracted by poor solvent precipitation using hexane. The extract was then analyzed using a JEOL JMN-ECZ400S. 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.

[0140] The content of each compound and the total amount of the three detected benzotriazole-based ultraviolet absorbers listed below were calculated. The content of each additive type of release agent, heat stabilizer, and colorant 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)

[0141] <Number of foreign objects> 50 g of the obtained recycled polycarbonate resin particles were dissolved in dichloromethane and filtered through a nylon mesh cloth with 20 μm openings. The number of foreign particles remaining on the nylon mesh cloth was measured using an SEM (Hitachi High-Tech SU3900) equipped with EDS (Oxford Instruments X-MaxN20) and analysis software (Oxford Instruments AZtec).

[0142] <Optical properties> The obtained recycled polycarbonate resin particles were placed in a small twin-screw kneader (Xplore Instruments, model MC15HT) and kneaded for 2 minutes at a barrel temperature of 270°C and a screw rotation speed of 100 rpm. The mixture was then molded in an attached injection molding machine (Xplore Instruments, model IM12) 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. The total light transmittance (TT), haze, L*, a*, and b* of the obtained molded plate were measured using a color and turbidity simultaneous measuring instrument COH 400 (manufactured by Nippon Denshoku Industries Co., Ltd.) (D65 light source, 10° field of view).

[0143] <Charpy impact strength> The obtained recycled polycarbonate resin particles were placed in a small twin-screw kneader (Xplore Instruments, model: MC15HT) and kneaded for 2 minutes at a barrel temperature of 270°C and a screw rotation speed of 100 rpm. The mixture was then molded in an attached injection molding machine (Xplore Instruments, model: IM12) at a cylinder temperature of 270°C and a mold temperature of 80°C to obtain bending test pieces measuring 10 mm in width, 80 mm in length, and 4 mm in thickness. The obtained bending test pieces were used to measure the notched Charpy impact strength in accordance with ISO179.

[0144] [Example 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 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 molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0145] [Examples 2 to 4] Recycled polycarbonate resin particles were obtained in the same manner as in Example 1, except that the contact time of the solvent extraction was carried out for the time shown in Table 1. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0146] [Example 5] Recycled polycarbonate resin pellets MT01300 manufactured by Matta (Xiamen) Technology Co., Ltd. were crushed in a cutter mill at 25°C. 200 g of the crushed product (average major axis: 1905 μm, average particle size: 1.75 mm) was placed in a 2-L flask with 800 mL of acetone, and the mixture was 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 molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0147] [Examples 6 to 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 resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0148] [Comparative Example 1] Using recycled polycarbonate resin pellets MT01300 (average major axis: 4074 μm, average particle size: 2.68 mm) manufactured by Matta (Xiamen) Technology Co., Ltd., the molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0149] Comparative Example 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. were dissolved in 1350 g of methylene chloride and filtered through a 1 μm mesh filter. The filtered polycarbonate resin solution and an alkaline aqueous solution (900 g of purified water, 11.3 g of NaOH) were placed in 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, separated, and the organic phase was recovered. This process was repeated twice until the aqueous phase became neutral. The washed polycarbonate resin solution and acid (900 g of purified water, 12.66 g of concentrated hydrochloric acid (35-37%)) were placed in 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, crushed, and dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0150] [Example 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 placed in a 2 L flask and stirred at 40°C for 6 hours. After stirring, the acetone was 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 molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0151] [Example 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 placed in a 2 L flask and stirred at 40°C for 6 hours. After stirring, 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 1,350 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, crushed, and dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0152] [Example 11] Recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kouyu Co., Ltd. were crushed in a cutter mill at 25°C. 200 g of the crushed product (average major axis: 2082 μm, average particle size: 1.82 mm) was charged into a 2-L flask and 800 mL of acetone was added. The mixture was 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 resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0153] [Example 12] Recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kouyu Co., Ltd. were crushed in a cutter mill at 25°C. 200 g of the crushed product (average major axis: 2082 μm, average particle size: 1.82 mm) was charged into a 2-L flask and 800 mL of acetone was added. The mixture was 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.

[0154] 150 g of the obtained recycled polycarbonate resin particles after solvent extraction was dissolved in 1,350 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, crushed, and dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0155] [Example 13] Recycled polycarbonate resin pellets PC-116A manufactured by Asahi Kouyu Co., Ltd. were crushed in a cutter mill at 25°C. 200 g of the crushed product (average major axis: 2082 μm, average particle size: 1.82 mm) was charged into a 2-L flask and 800 mL of acetone was added. The mixture was 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.

[0156] 150 g of the resulting recycled polycarbonate resin particles after solvent extraction 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 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 purified water, separated, and the organic phase was recovered. This procedure was repeated twice until the aqueous phase became neutral. The washed polycarbonate resin solution and acid (900 g of purified water, 12.66 g of concentrated hydrochloric acid (35-37%)) were placed in a 5 L flask, stirred, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 900 g of purified 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 resulting polycarbonate resin solution was poured into hot water at 80°C to remove methylene chloride, and the resulting mixture was pulverized and dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0157] [Example 14] 200 g of pulverized material (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 stirring, the acetone was 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 molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0158] [Example 15] 200 g of pulverized material (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 stirring, the acetone was removed by filtration and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles.

[0159] 150 g of the obtained recycled polycarbonate resin particles after solvent extraction was dissolved in 1,350 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, crushed, and dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0160] [Example 16] 200 g of pulverized material (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 stirring, the acetone was removed by filtration and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles.

[0161] 150 g of the resulting recycled polycarbonate resin particles after solvent extraction 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 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 purified water, separated, and the organic phase was recovered. This procedure was repeated twice until the aqueous phase became neutral. The washed polycarbonate resin solution and acid (900 g of purified water, 12.66 g of concentrated hydrochloric acid (35-37%)) were placed in a 5 L flask, stirred, and the organic phase was recovered. The recovered polycarbonate resin solution was washed with 900 g of purified 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 resulting polycarbonate resin solution was poured into hot water at 80°C to remove methylene chloride, and the resulting mixture was pulverized and dried at 120°C to obtain recycled polycarbonate resin particles. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0162] Comparative Example 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 content, additive content, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0163] [Example 17] Recycled polycarbonate resin particles were obtained in the same manner as in Example 11, except that propyl acetate was used instead of acetone. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0164] [Example 18] Recycled polycarbonate resin particles were obtained in the same manner as in Example 11, except that methanol was used instead of acetone. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0165] Comparative Example 4 Recycled polycarbonate resin particles were obtained in the same manner as in Example 11, except that hexane was used instead of acetone. The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0166] [Example 19] Recycled polycarbonate resin particles were obtained in the same manner as in Example 14, except that recycled polycarbonate resin pellets PC-T103 manufactured by Ningbo Topcentral New Material Co., Ltd. were freeze-pulverized to obtain a pulverized product (average major axis: 273 μm, average particle size: 0.26 mm). The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0167] [Example 20] Recycled polycarbonate resin particles were obtained in the same manner as in Example 15, except that recycled polycarbonate resin pellets PC-T103 manufactured by Ningbo Topcentral New Material Co., Ltd. were freeze-pulverized to obtain a pulverized product (average major axis: 273 μm, average particle size: 0.26 mm). The resulting recycled polycarbonate resin particles were evaluated for molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0168] Comparative Example 5 The crushed product (average major axis: 273 μm, average particle size: 0.26 mm) obtained by freeze-crushing recycled polycarbonate resin pellets PC-T103 manufactured by Ningbo Topcentral New Material Co., Ltd. was used to evaluate the molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength.

[0169] [Reference example 1] Using Teijin virgin polycarbonate resin pellets (Panlite L-1225Z100M), molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0170] [Reference example 2] Using Teijin virgin polycarbonate resin powder (Panlite L-1225WS), molecular weight distribution, oligomer content, additive content, foreign matter count, optical properties, and Charpy impact strength were evaluated.

[0171] [Table 1]

[0172] [Table 2]

[0173] 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, it is possible to adjust the color by blending an appropriate colorant, just as when using virgin polycarbonate resin. It is also clear that heat resistance (molded color) and transparency are further improved by reducing foreign matter and impurities through filtration and washing processes. [Industrial Applicability]

[0174] 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, can significantly improve the impact resistance that has been a problem with recycled polycarbonate resins. Furthermore, by reducing foreign matter and impurities, the particles can be widely used as a recycled material that has excellent heat resistance (color after molding) and transparency, and are suitable for use in the wide variety of applications in which virgin polycarbonate resins are used.

Claims

1. 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. 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.

3. 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.

4. 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.

5. 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.

6. 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.

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