Method for producing recycled polycarbonate resin particles, recycled polycarbonate resin particles, and recycled polycarbonate resin composition

Abstract

The objective is to provide a method for producing recycled polycarbonate resin particles with excellent color and transparency as a result of almost completely removing surface degradation materials. Furthermore, the objective is to provide recycled polycarbonate resin particles and recycled polycarbonate resin compositions with excellent color and transparency. [Solution] Solution b * A method for obtaining recycled polycarbonate resin particles from a yellowed and deteriorated recycled polycarbonate resin molded product having a value of 0.8 to 5.0, the method comprising the steps of (I) or (II) below. (I)(A-1) The surface layer of the recycled polycarbonate resin molded product is removed by contacting it with an organic solvent whose main solvent is a good solvent for polycarbonate resin, and solution b * (B-1) A process to obtain molded articles with improved hue until the value is -0.3 to 0.7 (organic solvent contact treatment process) and (B-1) A process to obtain recycled polycarbonate resin particles by crushing the molded articles obtained in the A-1 process (crushing process). (II)(B-2) A process to obtain a pulverized product by crushing a recycled polycarbonate resin molded product (crushing process) and (A-2) The surface layer of the pulverized product obtained in the B-2 process is removed by contacting it with an organic solvent mainly composed of a good solvent for polycarbonate resin, and solution b * A process to obtain recycled polycarbonate resin particles with improved hue until the value is between -0.3 and 0.7 (organic solvent contact treatment process).

Description

[Technical Field]

[0001] This invention relates to a method for producing recycled polycarbonate resin particles with excellent hue and transparency. It also relates to recycled polycarbonate resin particles and recycled polycarbonate resin compositions with excellent hue and transparency. [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 processability. In most current industrial manufacturing methods, plastic materials are not produced as substances with a single molecular weight, but rather as mixtures with a molecular weight distribution. Of these, low molecular weight components degrade the physical properties of plastic materials, so it is desirable to have a low content of them.

[0003] Furthermore, plastic materials are used with various additives added to improve weather resistance, flame retardancy, and design aesthetics. However, these additives and their modified forms often consist of low molecular weight components, which can impair the physical properties of the material. Therefore, the amount of additives used must be appropriately controlled.

[0004] In recent years, due to concerns about resource depletion and growing environmental awareness, recycling—the collection and reshaping of used plastic materials for reuse—has become increasingly popular.

[0005] Regarding recycled plastic materials, the resin deteriorates (decomposes) during the manufacturing (molding) and use processes, or various additives are added, resulting in a high need to remove low molecular weight substances compared to virgin resins.

[0006] In resin products, the surface, which comes into contact with oxygen and moisture and where ultraviolet light reaches without being attenuated by absorption by the resin, is the most susceptible to degradation. In the case of polycarbonate resin, some of the degradation products absorb ultraviolet light and play a role in preventing the degradation of the resin inside, so the impact of surface degradation is particularly significant.

[0007] Furthermore, recycled plastic materials have the disadvantage of being difficult to achieve specific colors because they are processed and refined from a mixture of waste plastics of various colors, making it difficult to identify the desired physical and chemical properties. Therefore, it is desirable to remove as many colorants as possible to facilitate color adjustment.

[0008] Conventionally, a method for extracting and removing low molecular weight substances by contacting a plastic material with an organic solvent that does not dissolve the plastic material has been known. For example, Patent Document 1 examines the appropriate ratio of low molecular weight components and the size of polycarbonate resin particles. However, Patent Document 1 pertains to virgin materials, and for recycled materials, where the amount and type of low molecular weight substances differ, the appropriate ratio of low molecular weight components and molecular weight distribution of polycarbonate resin particles will differ. Therefore, the appropriate ratio of low molecular weight components and particle size for recycled materials, as well as methods for achieving them, have not been examined.

[0009] Furthermore, various studies have been conducted on methods for recycling recovered plastic materials after removing surface degradation products. For example, Patent Document 2 describes washing recovered plastic materials with a solvent capable of dissolving surface degradation products and modifying them for use in chemical recycling or material recycling. However, Patent Document 2's primary objective is to efficiently remove surface degradation products, not to remove them almost completely. Therefore, it does not require the solvent to completely dissolve the polycarbonate resin. The recommended treatment solvent is rather an organic solvent containing an organic solvent whose Hansen solubility index distance to the polycarbonate resin is greater than 7.0 and less than 10.1, thereby promoting crystallization without completely dissolving the polycarbonate resin. Furthermore, the guidelines mention the difference in methylene chloride dissolution color and hue L before and after treatment as indicators of modification, but do not mention any guidelines that focus on the absolute value after treatment.

[0010] No methods have been studied for almost completely removing surface degradation materials from recovered polycarbonate resin, regardless of its condition. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 4-306227 [Patent Document 2] International Publication No. 2024 / 143360 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The object of the present invention is to provide a method for producing recycled polycarbonate resin particles that have excellent hue and transparency as a result of almost complete removal of surface degradation materials. Furthermore, the object is to provide recycled polycarbonate resin particles and recycled polycarbonate resin compositions that have excellent hue and transparency. [Means for solving the problem]

[0013] As a result of diligent research, the inventors have discovered that recycled polycarbonate resin particles with excellent hue and transparency can be provided by removing the surface layer of the surface and / or back surface of a yellowed and deteriorated recycled polycarbonate resin molded product by contacting it with a specific organic solvent, thus completing the present invention. In other words, according to the present invention, the problem to be solved is achieved as follows.

[0014] 1. Solution b * A method for obtaining recycled polycarbonate resin particles from a yellowed and deteriorated recycled polycarbonate resin molded product having a value of 0.8 to 5.0, the method comprising the steps of (I) or (II) below. (I)(A-1) The surface layer of the recycled polycarbonate resin molded product is removed by contacting it with an organic solvent whose main solvent is a good solvent for polycarbonate resin, and solution b * (B-1) A process to obtain molded articles with improved hue until the value is -0.3 to 0.7 (organic solvent contact treatment process) and (B-1) A process to obtain recycled polycarbonate resin particles by crushing the molded articles obtained in the A-1 process (crushing process). (II)(B-2) A process to obtain a pulverized product by crushing a recycled polycarbonate resin molded product (crushing process) and (A-2) The surface layer of the pulverized product obtained in the B-2 process is removed by contacting it with an organic solvent mainly composed of a good solvent for polycarbonate resin, and solution b * A process to obtain recycled polycarbonate resin particles with improved hue until the value is between -0.3 and 0.7 (organic solvent contact treatment process). 2. A method for producing recycled polycarbonate resin particles according to item 1, further comprising the steps of (C) dissolving recycled polycarbonate resin particles in a halogenated hydrocarbon solvent, filtering the resin solution obtained, and then removing the halogenated hydrocarbon solvent to produce recycled polycarbonate resin particles (dissolution, filtration, and granulation process). 3. A method for producing recycled polycarbonate resin particles according to item 1 or 2, further comprising (D) a step of washing the recycled polycarbonate resin particles or the resin solution obtained by dissolving the recycled polycarbonate resin particles in a halogenated hydrocarbon solvent with one or more of the following: water, alkali, acid, and brine (washing step). 4. Recycled polycarbonate resin particles obtained by any of the manufacturing methods described in item 1 to 3 above are further subjected to a solubility parameter of 16 to 30 MPa. 0.5 A method for producing recycled polycarbonate resin particles according to any one of paragraphs 1 to 3 above, comprising a step of contacting the particles with an organic solvent for 5 minutes to 10 hours (solvent extraction treatment step). 5. The method for producing recycled polycarbonate resin particles according to any one of the preceding items 1 to 4, wherein the organic solvent is an organic solvent having, as a main solvent, at least one good solvent for polycarbonate resin selected from the group consisting of 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, and dioxolane. 6. With respect to the total weight of the polycarbonate resin in the polycarbonate resin composition, (1) 5 to 100% by weight of recycled polycarbonate resin particles obtained by the production method according to any one of the preceding items 1 to 5, (2) solution b * 0 to 95% by weight of recycled polycarbonate resin particles derived from a recycled polycarbonate resin molded product that has not undergone yellowing degradation and has a value of 0.7 or less, and (3) 0 to 95% by weight of virgin polycarbonate resin, a polycarbonate resin composition. 7. With respect to the total weight of the polycarbonate resin in the polycarbonate resin composition, (1) 5 to 100% by weight of recycled polycarbonate resin particles obtained by the production method according to any one of the preceding items 1 to 5, (2) solution b * 0 to 95% by weight of recycled polycarbonate resin particles derived from a recycled polycarbonate resin molded product that has not undergone yellowing degradation and has a value of 0.7 or less, and (3) 0 to 95% by weight of virgin polycarbonate resin, a polycarbonate resin composition, wherein the hue (b * ) of the molded product of the polycarbonate resin composition is 0.5 to 20 lower in Δb * value than the hue (b * ) of the molded product of the polycarbonate resin composition obtained without removing the surface layer of a recycled polycarbonate resin molded product having a value of 0.8 to 5.0 and having undergone yellowing degradation, when using the recycled polycarbonate resin particles obtained without removing the surface layer instead of (1) the recycled polycarbonate resin particles. * A polycarbonate resin composition showing a value. 8. Solution b removed by contacting the surface layer with an organic solvent having, as a main solvent, a good solvent for polycarbonate resin * Recycled polycarbonate resin particles having a value of -0.3 to 0.7. 9. Recycled polycarbonate resin particles as described in item 8 above, wherein the organic solvent is an organic solvent whose main solvent is at least one good solvent for polycarbonate resin selected from the group consisting of 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, and dioxolane. 10. (1) 5 to 100% by weight of recycled polycarbonate resin particles as described in item 8 or 9 above, (2) solution b, relative to the total weight of the polycarbonate resin in the polycarbonate resin composition. * A polycarbonate resin composition comprising (3) 0 to 95% by weight of recycled polycarbonate resin particles derived from recycled polycarbonate resin molded products that have not yellowed or deteriorated and have a value of 0.7 or less, and (4) 0 to 95% by weight of virgin polycarbonate resin. 11. (1) 5 to 100% by weight of recycled polycarbonate resin particles as described in item 8 or 9 above, (2) solution b, relative to the total weight of polycarbonate resin in the polycarbonate resin composition. * A polycarbonate resin composition comprising (3) 0 to 95% by weight of recycled polycarbonate resin particles derived from recycled polycarbonate resin molded articles that have not yellowed or deteriorated and have a value of 0.7 or less, and 0 to 95% by weight of virgin polycarbonate resin, wherein the hue of the molded article of the polycarbonate resin composition (b * ) is solution b * (1) The hue (b) of a molded polycarbonate resin composition using recycled polycarbonate resin particles obtained without removing the surface layer of a yellowed and deteriorated recycled polycarbonate resin molded product with a value of 0.8 to 5.0 in place of the recycled polycarbonate resin particles. * ) Compared to Δb, it is 0.5 to 20 lower. * A polycarbonate resin composition showing a value. 12. A molded article made from a polycarbonate resin composition as described in any of paragraphs 6-7 or 10-11 above. [Effects of the Invention]

[0015] The recycled polycarbonate resin particles obtained by removing the surface layer of the surface and / or back surface of a yellowed and deteriorated recycled polycarbonate resin molded product by contacting it with an organic solvent can be widely used as a material for various molded products as a recycled material with excellent hue and transparency, thus providing extremely significant industrial benefits. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows the Raman intensity of the surface layer of a used polycarbonate sheet material for building materials that has yellowed and deteriorated, as determined by micro-Raman analysis of the surface exposed to ultraviolet light. [Figure 2] This figure shows the surface Raman intensity of a used polycarbonate sheet material for building materials that has not yellowed or deteriorated, as determined by micro-Raman analysis. [Modes for carrying out the invention]

[0017] The present invention will be described in detail below.

[0018] <Recycled polycarbonate resin molded products (raw material)> The recycled polycarbonate resin molded articles (raw materials) that can be used in the present invention refer to products and materials containing polycarbonate resin that have been put into the market as products and used by consumers, injection molded articles containing polycarbonate resin or crushed sprues or runners generated during injection molding, extruded articles such as films and sheets or crushed scraps generated during extrusion molding, etc., and recovery materials consisting of post-consumer materials, post-industrial materials, or a combination thereof may be used.

[0019] In this regard, there are no particular restrictions on the method of recovering recycled polycarbonate resin molded products (raw materials). Generally, for example, specialized companies such as waste collection companies and recycling companies can collect recovered products, remove (separate) different types of resins and other dissimilar materials, and then crush, wash, and dry the resulting flake-like material.

[0020] Recycled polycarbonate resin molded products (raw materials) used outdoors for extended periods gradually deteriorate due to exposure to ultraviolet rays and weather, resulting in yellowing and a decrease in molecular weight. Typical examples of recycled polycarbonate resin molded products (raw materials) used outdoors include building materials such as carports, transparent soundproof walls, construction equipment windows, and arcade canopies, as well as headlamp covers and automotive exterior materials.

[0021] Of these, micro-Raman analysis was performed on the surface of yellowed and deteriorated used polycarbonate sheet material for building materials that had been exposed to ultraviolet light under the following conditions. An increase in Raman intensity due to fluorescence was observed in the area from the surface down to several tens of micrometers, suggesting that only the area from the surface down to several tens of micrometers was discolored (Figure 1). In the case of recycled polycarbonate resin molded products (raw material) that were not yellowed and deteriorated, even though they were the same used polycarbonate sheet material for building materials, almost no increase in Raman intensity was observed (Figure 2). As a result, it is suggested that only the surface portion of the yellowed and deteriorated recycled polycarbonate resin molded products is deteriorated and discolored. (Micro-Raman spectrometer) NRS-4500 (manufactured by JASCO) (Basic conditions) Exposure time: 5 seconds, Number of accumulations: 1, Measurement range: 4,000~400cm -1 (Equipment conditions) Grating: L900, Laser excitation wavelength: 532nm, Objective lens: MPL100×, Slit: φ17μm, Laser intensity: 100% (Line analysis) 0.5 μm pitch → Total 150 μm analysis, 1608 cm -1 Analyze the change in peak height (Raman intensity).

[0022] As mentioned earlier, polycarbonate resin deteriorates when exposed to ultraviolet rays and the elements, but the surface is more severely affected by the elements. In the case of polycarbonate resin, it and some of its degradation products strongly absorb ultraviolet rays, so the ultraviolet rays do not reach the inside of the resin, and only the surface deteriorates. These degradation mechanisms, along with the results of the micro-Raman analysis mentioned earlier, suggest that only the surface layer of the resin product deteriorates.

[0023] Polycarbonate resin products can have different environmental conditions on each side depending on their shape and application. For example, in the case of construction machinery or building windows, the environment differs significantly between the exterior and interior sides. Even in products used in open systems such as carports and transparent soundproof walls, if the amount of UV radiation and the effects of wind and rain differ on each side (e.g., top and bottom, south and north), the degree of deterioration and the depth of the deteriorated layer will differ on each side.

[0024] <Polycarbonate resin> In the recycled polycarbonate resin molded articles (raw materials) used in the present invention, the polycarbonate resin is preferably one obtained by reacting a divalent phenol with a carbonate precursor. Examples of reaction methods include interfacial polymerization, molten transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds.

[0025] Typical examples of divalent phenols used here 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, and 4,4'-(p-phenyl Examples include bis(4-hydroxyphenyl)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 divalent phenols are bis(4-hydroxyphenyl)alkanes, among which bisphenol A is particularly preferred and widely used in terms of impact resistance.

[0026] In this invention, in addition to bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, it is also possible to use special polycarbonate resins manufactured using other divalent 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 some or all of the divalent phenol components are suitable for applications where dimensional changes due to water absorption and morphological stability are particularly demanding. These divalent phenols other than BPA are preferably used in an amount of 5 mol% or more, particularly 10 mol% or more, of the total divalent phenol components constituting the polycarbonate resin. In particular, when high rigidity and better hydrolysis resistance are required, the copolymer polycarbonate resins of (1) to (3) below are especially preferred. (1) A copolymer polycarbonate resin in which, of 100 mol% of the divalent phenol component constituting the polycarbonate resin, BPM is 20 to 80 mol% (more preferably 40 to 75 mol%, even more preferably 45 to 65 mol%) and BCF is 20 to 80 mol% (more preferably 25 to 60 mol%, even more preferably 35 to 55 mol%). (2) A copolymer polycarbonate resin in which, of 100 mol% of the divalent phenol component constituting the polycarbonate resin, BPA is 10 to 95 mol% (more preferably 50 to 90 mol%, even more preferably 60 to 85 mol%) and BCF is 5 to 90 mol% (more preferably 10 to 50 mol%, even more preferably 15 to 40 mol%). (3) A copolymer polycarbonate resin in which, of 100 mol% of the divalent phenol component constituting the polycarbonate resin, BPM is 20 to 80 mol% (more preferably 40 to 75 mol%, even more preferably 45 to 65 mol%) and Bis-TMC is 20 to 80 mol% (more preferably 25 to 60 mol%, even more preferably 35 to 55 mol%).

[0027] These special polycarbonate resins may be used individually or mixed in appropriate combinations of two or more types. They can also be mixed with commonly used bisphenol A type polycarbonate resins. The manufacturing methods and properties of these special polycarbonate resins are described in detail in, for example, Japanese Patent Publication No. 6-172508, Japanese Patent Publication No. 8-27370, Japanese Patent Publication No. 2001-55435, and Japanese Patent Publication No. 2002-117580.

[0028] Furthermore, among the various polycarbonate resins mentioned above, those whose copolymerization composition and other properties have been adjusted to bring the water absorption rate and Tg (glass transition temperature) within the following ranges exhibit excellent hydrolysis resistance of the polymer itself, as well as significantly superior low warping after molding. Therefore, they are particularly suitable for fields requiring morphological stability. (i) A polycarbonate resin having a water absorption rate of 0.05 to 0.15%, preferably 0.06 to 0.13%, and a Tg of 120 to 180°C, or (ii) A polycarbonate resin having a Tg of 160 to 250°C, preferably 170 to 230°C, and a water absorption rate of 0.10 to 0.30%, preferably 0.13 to 0.30%, more preferably 0.14 to 0.27%.

[0029] Here, the water absorption rate of the polycarbonate resin was measured using a disc-shaped test piece with a diameter of 45 mm and a thickness of 3.0 mm, after immersion in water at 23°C for 24 hours in accordance with ISO 62-1980. The glass transition temperature (Tg) was determined by differential scanning calorimeter (DSC) measurement in accordance with JIS K7121.

[0030] Carbonyl halides, diester carbonates, or haloformates are used as carbonate precursors, specifically including phosgene, diphenyl carbonate, or dihaloformates of divalent phenols.

[0031] When producing a polycarbonate resin by interfacial polymerization of the divalent phenol and the carbonate precursor, a catalyst, an end-terminating agent, an antioxidant to prevent oxidation of the divalent phenol, etc., may be used as needed. The polycarbonate resin of the present invention also includes a branched polycarbonate resin copolymerized with a trifunctional or polyfunctional aromatic compound, a polyester carbonate resin copolymerized with an aromatic or aliphatic (including alicyclic) bifunctional carboxylic acid, a copolymerized polycarbonate resin copolymerized with a bifunctional alcohol (including alicyclic), and a polyester carbonate resin copolymerized with both such bifunctional carboxylic acid and bifunctional alcohol. Furthermore, a mixture of two or more of the obtained polycarbonate resins may also be used.

[0032] Branched polycarbonate resins can impart properties such as drip prevention to the thermoplastic resin composition of the present invention. Examples of trifunctional or polyfunctional aromatic compounds used in such branched polycarbonate resins include phloroglucin, phloroglucides, or 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 include trisphenols such as hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol, tetra(4-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)ketone, 1,4-bis(4,4-dihydroxytriphenylmethyl)benzene, or trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and their acid chlorides, among which 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.

[0033] In branched polycarbonate resins, 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%, of the total 100 mol% of structural units derived from divalent phenols and those derived from such polyfunctional aromatic compounds. Furthermore, especially in the case of melt transesterification, branched structural units may be produced as a side reaction, but the amount of such branched structural units is also preferably 0.001 to 2.5 mol%, more preferably 0.005 to 1.5 mol%, and even more preferably 0.01 to 1.0 mol%, of the total 100 mol% of structural units derived from divalent phenols. The proportion of such branched structures can be calculated by 1H-NMR measurement.

[0034] Among aliphatic difunctional carboxylic acids, α,ω-dicarboxylic acids are preferred. Examples of aliphatic difunctional carboxylic acids include linear saturated aliphatic dicarboxylic acids such as sebacic acid (decanediic acid), dodecanediic acid, tetradecanediic acid, octadecanediic acid, and eicosanedioic acid, as well as alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. As for difunctional alcohols, alicyclic diols are more preferred, with examples including cyclohexanedimethanol, cyclohexanediol, and tricyclodecanedimethanol.

[0035] The reaction methods used in the present invention for producing polycarbonate resin, such as interfacial polymerization, molten transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds, are well-known methods described in various literatures and patent publications.

[0036] The viscosity-average molecular weight of the polycarbonate resin used in this invention is preferably 12,500 to 32,000, more preferably 16,000 to 28,000, and even more preferably 18,000 to 26,000. Polycarbonate resins with a viscosity-average molecular weight of less than 12,500 may not provide good mechanical properties. On the other hand, resin compositions obtained from polycarbonate resins with a viscosity-average molecular weight exceeding 32,000 may have poor moldability.

[0037] In this invention, the viscosity-average molecular weight is first calculated using the following formula: the specific viscosity (η SP The viscosity of the solution was determined using an Ostwald viscometer from a solution prepared by dissolving 0.7 g of polycarbonate in 100 ml of methylene chloride at 20°C. Specific viscosity (η SP ) = (t-t0) / t0 [t0 is the number of seconds for the methylene chloride to fall, and t is the number of seconds for the sample solution to fall.] The specific viscosity (η) SP The viscosity-average molecular weight M is calculated from 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 Furthermore, the viscosity-average molecular weight of the polycarbonate resin in the thermoplastic resin composition of the present invention is calculated in the following manner. Specifically, the composition is mixed with methylene chloride in an amount 20 to 30 times its weight to dissolve the soluble components in the composition. These soluble components are collected by Celite filtration. The solvent is then removed from the resulting solution. The solid after solvent removal is thoroughly dried to obtain a solid of the components that dissolve in methylene chloride. The specific viscosity at 20°C is determined from a solution obtained by dissolving 0.7 g of this solid in 100 ml of methylene chloride in the same manner as above, and the viscosity-average molecular weight M is calculated from this specific viscosity in the same manner as above.

[0038] A polycarbonate-polydiorganosiloxane copolymer resin can also be used as the polycarbonate resin of the present invention. Preferably, the polycarbonate-polydiorganosiloxane copolymer resin is a copolymer resin prepared by copolymerizing a divalent phenol represented by the following general formula (1) and a hydroxyaryl-terminated polydiorganosiloxane represented by the following general formula (3).

[0039] [ka]

[0040] [In the above general formula (1), R 1 and R 2Each of the following groups 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 carboxyl group. If there are multiple groups, they may be the same or different. e and f are integers from 1 to 4, and W is at least one group selected from the group consisting of a single bond or a group represented by the general formula (2) below.

[0041] [ka]

[0042] [In the above general formula (2), R 11 ,R 12 ,R 13 ,R 14 ,R 15 ,R 16 ,R 17 and R 18 Each of these 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 of these 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 carboxyl group. If there are multiple groups, they may be the same or different. g is an integer from 1 to 10, and h is an integer from 4 to 7.

[0043] [ka]

[0044] [In the above general formula (3), R 3 , R 4 , R 5 , R 6 , R 7 and R 8 Each of the following is independently a hydrogen atom, a C1-C12 alkyl group, or a C6-C12 substituted or unsubstituted aryl group; R9 and R10 are independently a hydrogen atom, a halogen atom, a C1-C10 alkyl group, and a C1-C10 alkoxy group, respectively; p is a natural number, q is 0 or a natural number, and p+q is a natural number between 10 and 300. X is a C2-C8 divalent aliphatic group.

[0045] Examples of divalent phenols (I) represented by 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-H 1,1-bis(4-hydroxyphenyl)fluorene, 2,2-diphenylmethane, 3,1-bis(4-hydroxyphenyl)cyclohexane, 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.

[0046] 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, with 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 being particularly preferred. Among these, 2,2-bis(4-hydroxyphenyl)propane, which has excellent strength and good durability, is the most suitable. These may be used individually or in combination of two or more.

[0047] As the hydroxyaryl-terminated polydiorganosiloxane represented by the above general formula (3), the following compounds are preferably used, for example.

[0048] [ka]

[0049] Hydroxyaryl-terminated polydiorganosiloxanes (II) can be easily produced by hydrosiliculation reaction of olefinic unsaturated carbon-carbon bonded phenols, preferably vinylphenol, 2-allylphenol, isopropenylphenol, and 2-methoxy-4-allylphenol, to the ends 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, and (2-allylphenol)-terminated polydimethylsiloxanes and (2-methoxy-4-allylphenol)-terminated polydimethylsiloxanes are particularly preferred. Hydroxyaryl-terminated polydiorganosiloxanes (II) preferably have a molecular weight distribution (Mw / Mn) of 3 or less. To further improve low outgassing and low-temperature impact resistance during high-temperature molding, 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. Exceeding this preferred upper limit may result in a large amount of outgassing during high-temperature molding and poor low-temperature impact resistance.

[0050] Furthermore, to achieve high impact resistance, the degree of diorganosiloxane polymerization (p+q) of the hydroxyaryl-terminated polydiorganosiloxane(II) is appropriately set to 10-300. This degree of diorganosiloxane polymerization (p+q) is preferably 10-200, more preferably 12-150, and even more preferably 14-100. Below the lower limit of this preferred range, the impact resistance characteristic of polycarbonate-polydiorganosiloxane copolymers is not effectively exhibited, and above the upper limit of this preferred range, appearance defects appear.

[0051] The polydiorganosiloxane content in the polycarbonate-polydiorganosiloxane copolymer resin usable in this invention is preferably 0.1 to 50% by weight. More preferably, the polydiorganosiloxane content is 0.5 to 30% by weight, and even more preferably 1 to 20% by weight. Above the lower limit of this preferred range, excellent impact resistance and flame retardancy are obtained, and below the upper limit of this preferred range, a stable appearance that is less affected by molding conditions is easily obtained. The degree of polydiorganosiloxane polymerization and the polydiorganosiloxane content can be calculated by 1H-NMR measurement.

[0052] In the present invention, only one hydroxyaryl-terminated polydiorganosiloxane(II) may be used, or two or more may be used. Furthermore, to the extent that it does not interfere with the present invention, other comonomers other than the above-mentioned divalent phenol (I) and hydroxyaryl-terminated polydiorganosiloxane (II) may be used in combination in a range of 10% by weight or less relative to the total weight of the copolymer.

[0053] In the present invention, a mixed solution containing an oligomer having terminal chloroformate groups is prepared in advance by the reaction of divalent phenol(I) with a carbonate ester-forming compound in a mixture of a water-insoluble organic solvent and an alkaline aqueous solution.

[0054] In producing the divalent phenol(I) oligomer, the entire amount of divalent phenol(I) used in the method of the present invention may be converted into an oligomer at once, or a portion of it may be added as a reaction material to the subsequent interfacial polycondensation reaction as a post-added monomer. The post-added monomer is added to expedite the subsequent polycondensation reaction, and it is not necessary to add it if it is not needed. The method of this oligomer formation reaction is not particularly limited, but it is generally preferable to carry it out in a solvent in the presence of an acid binder.

[0055] The proportion of ester-forming compounds used can be adjusted as appropriate, taking into account the stoichiometric ratio (equivalent) of the reaction. Furthermore, when using gaseous ester-forming compounds such as phosgene, a method of blowing them into the reaction system is preferably employed.

[0056] Examples of acid binders include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases such as pyridine, or mixtures thereof. The proportion of acid binder used should be determined appropriately, taking into account the stoichiometric ratio (equivalents) of the reaction, as described above. Specifically, it is preferable to use 2 equivalents or a slightly excess amount of acid binder relative to the number of moles of divalent phenol(I) used to form the oligomer (usually 1 mole corresponds to 2 equivalents).

[0057] As the aforementioned solvent, various reaction-inert solvents, such as those used in the production of known polycarbonates, can be used individually or as a mixed solvent. 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.

[0058] There are no particular restrictions on the reaction pressure for oligomer formation; it can be atmospheric pressure, pressurized pressure, 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 polymerization is often exothermic, water cooling or ice cooling is desirable. The reaction time depends on other conditions and cannot be specified in general, but it is usually carried out in 0.2 to 10 hours. The pH range for the oligomer formation reaction is the same as for known interfacial reaction conditions, and the pH is always adjusted to 10 or higher.

[0059] In this invention, a mixed solution containing an oligomer of divalent phenol (I) having terminal chloroformate groups is obtained, and while stirring the mixed solution, a 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, is added to the divalent phenol (I), and the hydroxyaryl-terminated polydiorganosiloxane (II) and the oligomer are subjected to interfacial polycondensation to obtain a polycarbonate-polydiorganosiloxane copolymer.

[0060] [ka]

[0061] (In the above general formula (3), R 3 , R 4 , R 5 , R 6 , R 7 and R 8 Each of these is independently a hydrogen atom, a C1-C12 alkyl group, or a C6-C12 substituted or unsubstituted aryl group, R 9 and R 10 Each of the following is independently a hydrogen atom, a halogen atom, an alkyl group with 1 to 10 carbon atoms, and an alkoxy group with 1 to 10 carbon atoms, where p is a natural number, q is 0 or a natural number, and p+q is a natural number between 10 and 300. X is a divalent aliphatic group with 2 to 8 carbon atoms.

[0062] When carrying out an interfacial polycondensation reaction, an acid binder may be added as appropriate, taking into consideration the stoichiometric ratio (equivalent) of the reaction. Examples of acid binders include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases such as pyridine, or mixtures thereof. Specifically, when adding a portion of the hydroxyaryl-terminated polydiorganosiloxane(II) or divalent phenol(I) as described above as a post-added monomer to this reaction step, it is preferable to use 2 equivalents or an excess amount of alkali relative to the total number of moles of the post-added divalent phenol(I) and hydroxyaryl-terminated polydiorganosiloxane(II) (usually 1 mole corresponds to 2 equivalents).

[0063] The polycondensation reaction between the divalent phenol (I) oligomer and the hydroxyaryl-terminated polydiorganosiloxane (II) is carried out by vigorously stirring the above mixture.

[0064] In such polymerization reactions, end-terminating agents or molecular weight modifiers are commonly used. Examples of end-terminating agents include compounds having a monovalent phenolic hydroxyl group, such as ordinary phenols, p-tert-butylphenol, p-cumylphenol, and tribromophenol, as well as long-chain alkylphenols, aliphatic carboxylic acid chlorides, aliphatic carboxylic acids, alkyl hydroxybenzoates, hydroxyphenylalkylates, and alkyl etherphenols. The amount used is in the range of 100 to 0.5 moles, preferably 50 to 2 moles, per 100 moles of all divalent phenolic compounds used, and it is naturally possible to use two or more compounds in combination.

[0065] To accelerate the polycondensation reaction, a catalyst such as a tertiary amine like triethylamine or a quaternary ammonium salt may be added. The reaction time for such polymerization is preferably 30 minutes or more, and more preferably 50 minutes or more. Optionally, a small amount of antioxidant such as sodium sulfite or hydrosulfide may be added.

[0066] Branching agents can be used in combination with the above-mentioned divalent phenolic compounds to form branched polycarbonate-polydiorganosiloxanes. Examples of trifunctional or polyfunctional aromatic compounds used in such branched polycarbonate-polydiorganosiloxane copolymer resins include phloroglucin, phloroglucid, or 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, and 4-{4-[1 Examples include trisphenols such as 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, or trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and their acid chlorides, among which 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, and 1,1,1-tris(4-hydroxyphenyl)ethane is particularly preferred. The proportion of polyfunctional compounds 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%, of the total amount of the polycarbonate-polydiorganosiloxane copolymer resin. 1 It can be calculated by 1H-NMR measurement.

[0067] The reaction pressure can be reduced, atmospheric, or pressurized, but it is usually preferable to use atmospheric pressure or the self-pressure of the reaction system. The reaction temperature is selected from the range of -20 to 50°C, and since polymerization often generates heat, water cooling or ice cooling is desirable. The reaction time varies depending on other conditions such as the reaction temperature and cannot be specified in general terms, but it is usually carried out in 0.5 to 10 hours.

[0068] Depending on the circumstances, the obtained polycarbonate-polydiorganosiloxane copolymer resin may be subjected to appropriate physical treatment (mixing, fractionation, etc.) and / or chemical treatment (polymer reaction, crosslinking, partial decomposition, etc.) to obtain the desired reduced viscosity [η SP It can also be obtained as a polycarbonate-polydiorganosiloxane copolymer resin of [c].

[0069] The resulting reaction product (crude product) can be recovered as a polycarbonate-polydiorganosiloxane copolymer resin of the desired purity (degree of purification) by various post-treatment methods, such as known separation and purification methods.

[0070] The average size of polydiorganosiloxane domains in polycarbonate-polydiorganosiloxane copolymer resin molded articles is preferably in the range of 1 to 40 nm. More preferably, this average size is 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, and above the upper limit of this preferred range, impact resistance may not be stably exhibited.

[0071] The average domain size and normalized dispersion of polydiorganosiloxane domains in the polycarbonate-polydiorganosiloxane copolymer resin molded product of this invention were evaluated by small-angle X-ray scattering (SAXS). Small-angle X-ray scattering is a method for measuring diffuse scattering and diffraction occurring in the small-angle region with a scattering angle (2θ) < 10° or less. In this small-angle X-ray scattering method, if there are regions with different electron densities of about 1 to 100 nm in size in the material, diffuse scattering of X-rays is measured due to the difference in electron density. The particle size of the object to be measured is determined based on this scattering angle and scattering intensity. In the case of polycarbonate-polydiorganosiloxane copolymer resin, which has an aggregated structure in which polydiorganosiloxane domains are dispersed in a polycarbonate polymer matrix, diffuse scattering of X-rays occurs due to the difference in electron density between the polycarbonate matrix and the polydiorganosiloxane domains. The scattering intensity I is measured at each scattering angle (2θ) in the range of less than 10° to obtain a small-angle X-ray scattering profile. Assuming that the polydiorganosiloxane domains are spherical and that there is variability in the particle size distribution, the average size and particle size distribution (normalized variance) of the polydiorganosiloxane domains are determined by simulating with commercially available analysis software using a hypothetical particle size and a hypothetical particle size distribution model. 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 by transmission electron microscopy. The average domain size refers to the numerical average of the individual domain sizes. 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 the polydiorganosiloxane domain size by the average domain size, and is expressed by the following equation (1).

[0072]

number

[0073] <Components other than polycarbonate resin in recycled polycarbonate resin (raw material)> In the present invention, recycled polycarbonate resin (raw material) can be used that contains known functional agents such as mold release agents, heat stabilizers, ultraviolet absorbers, flow modifiers, and antistatic agents as components other than the polycarbonate resin itself. The main additives that do not pose a problem when contained in the recycled polycarbonate resin used as a raw material are listed below.

[0074] (i) Release agent As a recycled polycarbonate resin (raw material) used in this invention, a release agent may also be used, provided that it does not impair the effects of the present invention. Examples of release agents include fatty acid esters, polyolefin waxes (such as polyethylene wax and 1-alkene polymers, and those modified with functional group-containing compounds such as acid modification can also be used), fluorine compounds (such as fluorine oils represented by polyfluoroalkyl ethers), paraffin wax, and beeswax. Among these, fatty acid esters are preferred in terms of availability, release properties, and transparency. The release agent is preferably contained in an amount of 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 recycled polycarbonate resin (raw material). This is because when the content is above the lower limit of the above range, the effect of improving release properties is clearly exhibited, and when it is below the upper limit, adverse effects such as mold contamination during molding are reduced.

[0075] The fatty acid esters used as preferred release agents among those mentioned above will be described in more detail. Such fatty acid esters are esters of an aliphatic alcohol and an aliphatic carboxylic acid. Such aliphatic alcohol may be a monohydric alcohol or a polyhydric alcohol with two or more hydric values. The number of carbon atoms in the alcohol is preferably in the range of 3 to 32, and 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, polyglycerol (triglycerol to hexaglycerol), ditrimethylolpropane, xylitol, sorbitol, and mannitol. Polyhydric alcohols are more preferably used in fatty acid esters.

[0076] On the other hand, aliphatic carboxylic acids preferably have 3 to 32 carbon atoms, and aliphatic carboxylic acids with 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, eicosanic acid, and docosanic 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 with 14 to 20 carbon atoms are preferred. Saturated aliphatic carboxylic acids are particularly preferred. Since such aliphatic carboxylic acids are usually produced from natural oils and fats such as animal fats (beef tallow and lard, etc.) and vegetable oils (palm oil, etc.), these aliphatic carboxylic acids are usually mixtures containing other carboxylic acid components with different numbers of carbon atoms. Therefore, the production of aliphatic carboxylic acids also consists of mixtures produced from such natural oils and fats containing other carboxylic acid components. For fatty acid esters, an acid value of 20 or less (which can be substantially 0) is preferably used. However, in the case of full esters, it is preferable to contain at least some free fatty acids to improve mold release properties, and in this respect, an acid value in the range of 3 to 15 is preferably used for full esters. Furthermore, an iodine value of fatty acid esters is preferably 10 or less (which can be substantially 0). These properties can be determined by the method specified in JIS K 0070.

[0077] The aforementioned fatty acid esters may be either partial esters or full esters, but partial esters are preferred in terms of better mold release properties and durability, and glycerin monoesters are particularly preferred. Glycerin monoesters mainly consist of glycerin and a fatty acid monoester. Suitable fatty acids include saturated fatty acids such as stearic acid, palmitic acid, behenic acid, arachidic acid, montanic acid, and lauric acid, and unsaturated fatty acids such as oleic acid, linoleic acid, and sorbic acid. Glycerin monoesters mainly composed of stearic acid, behenic acid, and palmitic acid are particularly preferred. These fatty acids are synthesized from natural fatty acids and, as described above, are mixtures. Even in such cases, it is preferable to use glycerin monoesters in the fatty acid ester that account for 60% by weight or more.

[0078] It should be noted that partial esters are often inferior to full esters in terms of thermal stability. 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 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 conventional methods and then purifying them by molecular distillation or the like.

[0079] Specifically, one method involves removing gaseous and low-boiling-point substances using a spray nozzle degassing apparatus, then removing polyhydric alcohols such as glycerin using a drip-film distillation apparatus at a distillation temperature of 120-150°C and a vacuum of 0.01-0.03 kPa, and finally obtaining high-purity fatty acid partial esters as distillates using a centrifugal molecular distillation apparatus 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. By repeatedly performing molecular distillation on the obtained distillates, the purity can be further increased, and fatty acid partial esters with even lower sodium metal content can be obtained. It is also important to prevent contamination from the external environment by thoroughly cleaning the inside of the molecular distillation apparatus using appropriate methods beforehand and by improving airtightness. Such fatty acid esters are available from specialized suppliers (e.g., Riken Vitamin Co., Ltd.).

[0080] (ii) Phosphate stabilizers In the present invention, recycled polycarbonate resin (raw material) may also be used that contains various phosphorus-based stabilizers, primarily for the purpose of improving its thermal stability during molding. Examples of such phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphonic acid, phosphonic acid, and esters thereof. Furthermore, such phosphorus-based stabilizers may include tertiary phosphines.

[0081] Specifically, examples of phosphite compounds include triphenyl phosphite, tris(nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, tris(diethylphenyl) phosphite, tris(di-iso-propylphenyl) phosphite, and tris(di-n-butylphenyl) phosphite. Examples include 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, phenylbisphenol A pentaerythritol diphosphite, bis(nonylphenyl) pentaerythritol diphosphite, and dicyclohexyl pentaerythritol diphosphite.

[0082] Furthermore, other phosphite compounds that react with divalent phenols to form a cyclic structure may also be used. Examples include 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.

[0083] Examples of phosphate compounds include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenylcresyl phosphate, diphenylmonoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, and diisopropyl phosphate, with triphenyl phosphate and trimethyl phosphate being preferred.

[0084] Examples of phosphonite compounds include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, bis(2,4-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, and bis 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, with tetrakis(di-tert-butylphenyl)-biphenylenediphosphonite and bis(di-tert-butylphenyl)-phenyl-phenylphosphonite being preferred, and tetrakis(2,4-di-tert-butylphenyl)-biphenylenediphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite being more preferred. Such phosphonite compounds can be used in combination with phosphite compounds having an aryl group substituted with two or more alkyl groups, and this is preferable.

[0085] Examples of phosphonate compounds include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.

[0086] 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.

[0087] The phosphorus-based stabilizers described above may be used not only individually but also in combination of two or more. Among the phosphorus-based stabilizers described above, phosphite compounds or phosphonite compounds are preferred. In particular, tris(2,4-di-tert-butylphenyl)phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite are preferred. Combinations of these with phosphate compounds are also preferred embodiments.

[0088] (iii) Hindered phenol stabilizers (antioxidants) As a recycled polycarbonate resin (raw material) used in the present invention, a material containing a hindered phenol stabilizer is also available, primarily for the purpose of improving its thermal stability during molding and its heat aging resistance. Examples of such hindered phenol stabilizers include α-tocopherol, butylhydroxytoluene, cinapyl alcohol, vitamin E, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenol)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'-dimethylenebis(6-α-methylbenzyl-p-cresol)2,2'-ethyl Lyden-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-methyl6-(3-tert-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1,-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-Thiobis(4-methyl-6-tert-butylphenol), bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4,4'-di-thiobis(2,6-di-tert-butylphenol), 4,4'-tri-thiobis(2,6-di-tert-butylphenol), 2,2-thiodiethylenebis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3',5'-di-tert-butylanilino)-1,3,5-triazine, N,N'-Hexamethylenebis-(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 1,1 Examples include 3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxyphenyl)isocyanurate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, and tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane. All of these are readily available. The above-mentioned hindered phenol antioxidants may be used alone or in combination of two or more.

[0089] The amount of (ii) phosphorus-based stabilizer and / or (iii) hindered phenol-based antioxidant described above is 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 recycled polycarbonate resin (raw material). If the amount of stabilizer is too little compared to the above range, it is difficult to obtain a good stabilization effect, and if it is too much compared to the above range, it may conversely cause a decrease in the physical properties of the material or contamination of the mold during molding.

[0090] In the present invention, recycled polycarbonate resin (raw material) may also be used in which other antioxidants other than the above-mentioned hindered phenol-based antioxidants are used as appropriate. Examples of such other antioxidants include pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-laurylthiopropionate), and glycerol-3-stearylthiopropionate. The amount of these other antioxidants used is preferably 0.001 to 0.05 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material).

[0091] (iv) UV absorbers In this invention, recycled polycarbonate resin (raw material) containing an ultraviolet absorber can also be used. Examples of UV absorbers specifically include benzophenone-based compounds such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-bendyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxytrihydridebenzophenone, 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.

[0092] Specifically, examples of UV absorbers include benzotriazole-based benzotriazoles 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-benzotriazole-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, and 2-(2-hydroxy-5-tert-octylphenyl) Examples of polymers having a 2-hydroxyphenyl-2H-benzotriazole skeleton include 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-benzoxazine-4-one), and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, as well as copolymers of 2-(2'-hydroxy-5-methacryloxyethylphenyl)-2H-benzotriazole with a vinyl monomer copolymerizable with the monomer, and copolymers of 2-(2'-hydroxy-5-acryloxyethylphenyl)-2H-benzotriazole with a vinyl monomer copolymerizable with the monomer.

[0093] Examples of UV absorbers include, specifically, hydroxyphenyltriazine compounds such as 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-hexyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-methyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-ethyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-propyloxyphenol, and 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-butyloxyphenol. Furthermore, examples include compounds in which the phenyl group of the above example compounds has been replaced with a 2,4-dimethylphenyl group, such as 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-hexyloxyphenol.

[0094] Examples of cyclic iminoester-based ultraviolet absorbers include 2,2'-p-phenylenebis(3,1-benzoxazine-4-one), 2,2'-(4,4'-diphenylene)bis(3,1-benzoxazine-4-one), and 2,2'-(2,6-naphthalene)bis(3,1-benzoxazine-4-one).

[0095] Examples of UV absorbers include cyanoacrylate-based 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.

[0096] Furthermore, the above-mentioned ultraviolet absorber may also be a polymer-type ultraviolet absorber obtained by copolymerizing such ultraviolet-absorbing monomer and / or a photostable monomer having a hindered amine structure with a monomer such as an alkyl (meth)acrylate, by adopting the structure of a monomer compound that can be radically polymerized. Suitable examples of the above-mentioned ultraviolet-absorbing monomer include compounds containing a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a cyclic iminoester skeleton, and a cyanoacrylate skeleton in the ester substituent of a (meth)acrylic acid ester.

[0097] Among the above, benzotriazole and hydroxyphenyltriazine types are preferred in terms of ultraviolet absorption capacity, while cyclic iminoester and cyanoacrylate types are preferred in terms of heat resistance and hue. The above ultraviolet absorbers may be used individually or as a mixture of two or more.

[0098] The UV absorber is preferably used in an amount of 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 especially preferably 0.05 to 0.5 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material).

[0099] (v) Flow modifiers As a recycled polycarbonate resin (raw material) used in the present invention, a material containing a flow modifier may also be used, provided that it does not impair the effects of the present invention. Suitable examples of such flow modifiers include styrene oligomers, polycarbonate oligomers (including highly branched, hyperbranched, and cyclic oligomer types), polyalkylene terephthalate oligomers (including highly branched, hyperbranched, and cyclic oligomer types), highly branched and hyperbranched aliphatic polyester oligomers, terpene resins, and polycaprolactone. Such flow modifiers are used in an amount of preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, and even more preferably 2 to 15 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material). Polycaprolactone is particularly preferred, and the composition ratio is particularly preferably 2 to 7 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material). The molecular weight of polycaprolactone, expressed as a number-average molecular weight, is between 1,000 and 70,000, with 1,500 to 40,000 being preferred, 2,000 to 30,000 being more preferred, and 2,500 to 15,000 being even more preferred.

[0100] (vi) Antistatic agents In the present invention, recycled polycarbonate resin (raw material) can also be used that contains an antistatic agent primarily for the purpose of improving its antistatic properties. As the antistatic agent, phosphonium sulfonate salts, phosphite esters, caprolactone polymers, etc., can be used, with phosphonium sulfonate salts being preferred. Specific examples of such phosphonium sulfonate salts 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 ease of availability. The amount of antistatic agent is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight, even more preferably 0.3 to 2.0 parts by weight, and particularly preferably 0.5 to 1.8 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material). This is because an antistatic effect is obtained at 0.1 parts by weight or more, and at 5.0 parts by weight or less, excellent transparency and mechanical strength are achieved, and silvering or peeling does not occur on the surface of the molded product, making it less likely to cause appearance defects.

[0101] In addition to the recycled polycarbonate resin (raw material) used in this invention, those containing various additives such as bluing agents, fluorescent dyes, flame retardants, and dyes and pigments can also be used. These can be appropriately selected and used within a range that does not impair the effects of the present invention.

[0102] Blueing agents typically contain 0.05 to 3.0 ppm (by weight) of blueing agent in recycled polycarbonate resin (raw material). Representative examples of blueing agents include Bayer's Macrolex Violet B and Macrolex Blue RR, and Clariant's Polysynthrene Blue RLS.

[0103] Examples of fluorescent dyes (including fluorescent whitening agents) 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, thiaidine-based fluorescent dyes, and diaminostilbene-based fluorescent dyes. Fluorescent dyes (including fluorescent whitening agents) are preferably blended in an amount of 0.0001 to 0.1 parts by weight per 100 parts by weight of recycled polycarbonate resin (raw material).

[0104] Examples of flame retardants include metal sulfonate salt-based flame retardants, halogen-containing compound-based flame retardants, phosphorus-containing compound-based flame retardants, and silicon-containing compound-based flame retardants. Among these, metal sulfonate salt-based flame retardants are preferred. The flame retardant is usually blended in an amount of 0.01 to 1 part by weight, and more preferably in the range of 0.05 to 1 part by weight, per 100 parts by weight of recycled polycarbonate resin (raw material).

[0105] The virgin polycarbonate resin produced by polymerization is solution b * The value is usually 0 to 0.1, and the resin is colorless to pale yellow transparent, but the recycled polycarbonate resin product used in this invention is a product that has had various additives added to it, and in terms of color tone, the aforementioned bluing agent and the like have been added to the solution b before use so that users can feel comfortable with it. * The majority of products are adjusted so that the value is between -0.3 and 0.7.

[0106] <Method for producing recycled polycarbonate resin particles> The present invention relates to solution b* A method for obtaining recycled polycarbonate resin particles from a yellowed and deteriorated recycled polycarbonate resin molded product having a value of 0.8 to 5.0, wherein the method for producing recycled polycarbonate resin particles comprises the following steps (I) or (II).

[0107] (I)(A-1) The surface layer of the recycled polycarbonate resin molded product is removed by contacting it with an organic solvent whose main solvent is a good solvent for polycarbonate resin, and solution b * (B-1) A process to obtain molded articles with improved hue until the value is -0.3 to 0.7 (organic solvent contact treatment process) and (B-1) A process to obtain recycled polycarbonate resin particles by crushing the molded articles obtained in the A-1 process (crushing process). (II)(B-2) A process to obtain a pulverized product by crushing a recycled polycarbonate resin molded product (crushing process) and (A-2) The surface layer of the pulverized product obtained in the B-2 process is removed by contacting it with an organic solvent mainly composed of a good solvent for polycarbonate resin, and solution b * A process to obtain recycled polycarbonate resin particles with improved hue until the value is between -0.3 and 0.7 (organic solvent contact treatment process). In this invention, a step is performed to remove the surface layer of a recycled polycarbonate resin molded product or the surface layer of a pulverized product by contacting it with an organic solvent whose main solvent is a good solvent for polycarbonate resin (organic solvent contact treatment step). In addition, in this invention, a step is performed to pulverize the molded product (pulverization treatment step).

[0108] The following describes the process of removing the surface layer by contacting it with an organic solvent primarily composed of polycarbonate resin (organic solvent contact process) and the process of pulverizing the molded product (pulverization process).

[0109] <Solid solvent contact treatment process> There are no particular restrictions on the method for contacting the surface of a recycled polycarbonate resin molded product (raw material) or pulverized product with an organic solvent mainly composed of a good solvent for polycarbonate resin, and either (i) a batch method, (ii) a continuous method, or both can be selected. The (i) batch method, as described in Japanese Patent Publication No. 63-278929 and Japanese Patent Publication No. 64-6020, involves placing polycarbonate powder and an organic solvent in a container, stirring, and then separating the solid and liquid. (ii) The continuous method, as described in Japanese Patent Publication No. 4-306227 and Japanese Patent Publication No. 4-145903, is a manufacturing method characterized by bringing an organic solvent into contact with polycarbonate powder, in which the polycarbonate powder is introduced from the top of the extraction container and the organic solvent is introduced from the bottom of the extraction container, and the organic solvent is discharged from the top of the extraction container while continuous countercurrent contact is maintained, the polycarbonate powder is allowed to settle naturally in the organic solvent without stirring, is removed from the bottom of the extraction container as a slurry, and then dried after solid-liquid separation. As reported in Japanese Patent Publication No. 4-306227, (i) the batch method is inefficient for industrial use and has the disadvantage that the polycarbonate particles fuse together due to prolonged stirring, hindering the efficiency of solid-liquid separation. For this reason, industrially, it is preferable to adopt the (ii) continuous method.

[0110] As the organic solvent to be brought into contact with the polycarbonate resin, a good solvent for polycarbonate resin is selected in order to completely dissolve a certain thickness of the polycarbonate resin from the surface. Specifically, the organic solvent is one in which at least one good solvent selected from the group consisting of 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, and dioxolane is the main solvent, with methylene chloride being particularly preferred.

[0111] Here, an organic solvent primarily composed of a good solvent means one in which the good solvent preferably accounts for 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 100% or more by weight of the good solvent relative to the total amount of the organic solvent.

[0112] Furthermore, the above organic solvent may contain a poor solvent that does not cause polymer precipitation. Examples of such poor solvents include aliphatic hydrocarbons such as pentane, hexane, and heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

[0113] The end of the contact process between recycled polycarbonate resin and organic solvent (organic solvent contact treatment process) is determined by sampling the treated recycled polycarbonate resin molded product (raw material) or pulverized product and testing solution b * Measure the value and solution b * This can be determined by the value being between -0.3 and 0.7. Solution b * A value of -0.2 to 0.55 indicates a more appropriate end time for the organic solvent contact treatment process, while a value of -0.1 to 0.45 indicates the most appropriate end time for the organic solvent contact treatment process. Solution b * If the value exceeds 0.7, the removal of surface degradation materials is insufficient, resulting in a deterioration of the color of the molded product. Note that solution b * The value is obtained by dissolving 1 g of recycled polycarbonate resin in 5 ml of methylene chloride, filtering it through a PTFE filter with a mesh size of 0.22 μm, and then measuring the resulting solution according to CIE1976(L * a * b * The values ​​of the color system are measured using a UV-Vis-Infrared Spectrophotometer V-770DS (manufactured by JASCO). Furthermore, if the dissolution, filtration, and granulation process described later is to be carried out, it is preferable to perform the dissolution, filtration, and granulation process immediately following this process.

[0114] <Grinding Process> A mechanical pulverization method is preferred for pulverizing recycled polycarbonate resin molded products. For example, recycled polycarbonate resin molded products are mechanically pulverized to produce recycled polycarbonate resin particles (pulverized products) having the desired average major diameter and average average particle size. According to the mechanical pulverization method, recycled polycarbonate resin particles can be produced, for example, by the following method.

[0115] Recycled polycarbonate resin molded products may be crushed after freezing, or they may be crushed at room temperature. After coarse crushing with a crusher, the recycled polycarbonate resin molded products can be further crushed with a pulverizer to the desired average major diameter and average particle size. The crusher can be a known device for crushing recycled polycarbonate resin molded products, such as a single-shaft crusher or a twin-shaft crusher. The pulverizer can be a known device for further fine crushing the coarsely crushed recycled polycarbonate resin molded products. Examples of such devices include compression crushers (roll crushers, etc.), impact crushers (impact crushers, hammer mills, etc.), cutting or shearing crushers (cutter mills, reciprocating crushers, low-speed rotary crushers (twin-shaft shearing crushers, etc.), etc.), impact shearing crushers (shredders, etc.), and various fine crushers (ball mills, disc mills, pin mills, hammer mills, turbo mills, jet mills, etc.). Among the above, cutting or shearing type grinders are preferred because they can directly supply molded products, have excellent grinding efficiency, and can accommodate the required particle size. Among these, low-speed rotary grinders are preferred because they have a suitable bulk density even for highly tough exterior molded products, making it easier to obtain desirable pulverized material. Any type of low-speed rotary grinder, such as single-shaft, double-shaft, or triple-shaft type, can be used.

[0116] In mechanical pulverization, frictional heat generated from recycled polycarbonate resin particles during pulverization can cause the particles to fuse together, potentially resulting in particles with the desired average major diameter and average particle size. Therefore, the thermoplastic resin may be cooled and brittle using liquid nitrogen or the like before pulverization.

[0117] The pulverization process can be performed either before or after the aforementioned organic solvent contact process, but it is preferable to perform the pulverization process first in order to efficiently bring the recycled polycarbonate resin into contact with the specific organic solvent.

[0118] <Dissolution, filtration, and granulation process> In the present invention, in order to reduce foreign matter in recycled polycarbonate resin particles, recycled polycarbonate resin particles may be dissolved in a halogenated hydrocarbon solvent, the recycled polycarbonate resin solution may be filtered, and then the halogenated hydrocarbon solvent may be removed to obtain recycled polycarbonate resin particles. The halogenated hydrocarbon solvent used in this case is a good solvent for polycarbonate resin and is immiscible with water. The halogenated hydrocarbon solvent referred to in the present invention is mainly 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. Particularly preferably, methylene chloride (boiling point at atmospheric pressure 40°C) is used. Preferably, the halogenated hydrocarbon solvent is one in which 90% or more by volume is a good solvent, and particularly preferably a solvent substantially composed of a good solvent is used.

[0119] 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. This is because, within this concentration range, the solution concentration is appropriate, it is easy to handle in industrial production equipment, the solution is easy to wash, the filtration efficiency is good, and there is not too much halogenated hydrocarbon solvent, so excessive energy is not required when removing the solvent afterward, which is advantageous in terms of economic production.

[0120] Furthermore, the halogenated hydrocarbon solvent used in the present invention may contain a poor solvent that does not cause polymer precipitation. Examples of such poor solvents include aliphatic hydrocarbons such as pentane, hexane, and heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

[0121] The recycled polycarbonate resin particle of the present invention can be obtained by granulating and drying the recycled polycarbonate resin solution after filtration. There are no particular limitations on granulation, drying, etc., and known methods can be used.

[0122] <Cleaning Process> To reduce impurities in recycled polycarbonate resin particles, recycled polycarbonate resin particles or a resin solution obtained by dissolving recycled polycarbonate resin particles in a halogenated hydrocarbon solvent may be washed with one or more of water, alkali, acid, and brine. In the case of a resin solution, the halogenated hydrocarbon solvent may then be removed to obtain recycled polycarbonate resin particles. Among these, the washing treatment using a resin solution is preferred.

[0123] After dissolving recycled polycarbonate resin particles in a halogenated hydrocarbon solvent, the recycled polycarbonate resin solution is mixed and stirred with water, alkali, acid, or brine. The mixture is then allowed to stand or separated from the aqueous phase using a centrifuge, and the aqueous phase is repeatedly separated to remove the aqueous phase, thereby removing water-soluble impurities. Water washing, alkali washing, acid washing, and brine washing can be performed in any order or combination, but when performing alkali washing, acid washing, or brine washing, the water washing is carried out 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 washing, alkali washing, acid washing, and brine washing, water-soluble impurities are removed, and the resulting recycled polycarbonate resin has a good hue. The washing treatment may be performed before or after the dissolution, filtration, and granulation process described above.

[0124] The recycled polycarbonate resin solution after washing can be granulated and dried to obtain the recycled polycarbonate resin particles of the present invention. There are no particular limitations on granulation, drying, etc., and known methods can be used.

[0125] <Solvent extraction process> The recycled polycarbonate resin particles of the present invention may be subjected to solvent extraction treatment for the purpose of removing impurities such as monomers, oligomers, additives, and modified products thereof from the recycled polycarbonate resin molded product (raw material) which is the raw material.

[0126] In the solvent extraction process, monomers, oligomers, additives, and their modified forms present in the recycled polycarbonate resin molded product (raw material) are eluted into an organic solvent. The solid and liquid are then separated, and after drying at 80-140°C, the recycled polycarbonate resin particles of the present invention can be obtained. The organic solvent used for extraction and separation can usually be industrially distilled to remove eluted substances and reused repeatedly.

[0127] The extraction method using an organic solvent can be selected from either (i) batch or (ii) continuous methods. (i) The batch method, as described in, for example, Japanese Patent Publication No. 63-278929 and Japanese Patent Publication No. 64-6020, involves placing polycarbonate powder and an organic solvent in a container, stirring, and then separating the solid and liquid. (ii) The continuous method, as described in, for example, Japanese Patent Publication No. 4-306227 and Japanese Patent Publication No. 4-145903, is a manufacturing method characterized by, when extracting impurities from polycarbonate powder with an organic solvent, introducing the polycarbonate powder from the top of the extraction container and the organic solvent from the bottom of the extraction container, and discharging the organic solvent from the top of the extraction container while continuously countercurrent contact is maintained, allowing the polycarbonate powder to settle naturally in the organic solvent without stirring to form a slurry which is then removed from the bottom of the extraction container, separated into solid and liquid, and dried. As reported in Japanese Patent Publication No. 4-306227, (i) the batch method is inefficient for industrial use and has the disadvantage of generating fine polycarbonate powder due to prolonged stirring, which hinders solid-liquid separation efficiency. Furthermore, it has been confirmed that when acetone used as an organic solvent is separated, recovered, and reused repeatedly, the amount of residual methylene chloride in the dried powder obtained by acetone extraction gradually increases. For this reason, (ii) the continuous method is preferable for industrial use.

[0128] The organic solvents used in the solvent extraction process have a solubility parameter of 16-30 MPa. 0.5 It is preferable to use an organic solvent, and the pressure should be 17-25 MPa. 0.5 More preferably, 18-22 MPa 0.5This is even more preferable. Within the above range, monomers, oligomers, additives, and their modified products present in recycled polycarbonate resin (raw material) can be efficiently extracted.

[0129] Solubility parameter (sometimes called δ or SP value). Unit: MPa 0.5 ) is a value defined by the regular solution theory introduced by Hildebrand, and is determined by the molar heat of vaporization and molar volume of the compound in question. Here, the solubility parameter is 16-30 (MPa). 0.5 As organic solvents, non-halogenated organic solvents such as acetone, methyl ethyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, and diethyl ketone (compounds having a carbonyl group), 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 are preferred. Among these, acetone is more preferred because it can efficiently extract monomers, oligomers, additives, and their modified products, has a low boiling point, and is easy to separate and recover by distillation. Furthermore, two or more of these organic solvents can be used in combination as needed.

[0130] Regarding the contact time with the organic solvent in the solvent extraction process, in the case of a batch process it is simply the processing time, but in the case of a continuous process, for example, if the recycled polycarbonate resin particles are introduced from the top of the extraction container and the organic solvent is introduced from the bottom of the extraction container, and the organic solvent is discharged from the top of the extraction container while the amount of liquid in the extraction container is kept constant, and the recycled polycarbonate resin particles are allowed to settle naturally in the organic solvent and removed from the bottom of the extraction container as a slurry, the contact time is expressed by the following formula (2). Contact time (hr) = Volume of liquid in the extraction container (m³)3 ) / The rate at which resin and organic solvents are added (=removed) (m 3 / hr)···(2)

[0131] In the solvent extraction process, the contact time with the organic solvent is preferably 5 minutes to 10 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 process, and preferably 5 minutes to 10 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 process. Within the above ranges, monomers, oligomers, additives, and their modified products can be extracted efficiently, which is industrially preferable.

[0132] The temperature of the organic solvent introduced significantly affects the extraction efficiency. Typically, it should be 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, it is preferably 10 to 55°C, more preferably 30 to 50°C, and it is preferable to equip the extraction apparatus with a jacket or a heating mechanism.

[0133] When both dissolution, filtration, and granulation processes, and solvent extraction processes are performed, the solvent extraction process may be carried out either before or after the dissolution, filtration, and granulation processes. However, performing the solvent extraction process after the dissolution, filtration, and granulation processes is preferable because the specific surface area of ​​the granulated polycarbonate resin is large, resulting in higher efficiency of the solvent extraction process.

[0134] <Recycled polycarbonate resin particles> In the present invention, recycled polycarbonate resin particles are obtained by removing their surface layer by contacting them with an organic solvent whose main solvent is a good solvent for polycarbonate resin, in solution b. * These are recycled polycarbonate resin particles with a value of -0.3 to 0.7. Solution b * A value of -0.2 to 0.6 is preferred for solution b. * A value of -0.2 to 0.55 is more preferable, and -0.1 to 0.45 is even more preferable. Solution b *If the value exceeds the upper limit, the removal of surface degradation is insufficient, and the resulting recycled polycarbonate resin and molded product will have a poor hue, which is undesirable. Solution b * If the value is below the lower limit, the color becomes too blue, which is undesirable as it is inferior to the hue of recycled polycarbonate resin and molded products.

[0135] Note that solution b * The value is obtained by dissolving 1 g of recycled polycarbonate resin in 5 ml of methylene chloride, filtering it through a PTFE filter with a mesh size of 0.22 μm, and then measuring the resulting solution according to CIE1976(L * a * b * The values ​​of the color system are measured using a UV-Vis-Infrared Spectrophotometer V-770DS (manufactured by JASCO).

[0136] As the above organic solvent, a good solvent for polycarbonate resin is selected in order to completely dissolve a certain thickness of polycarbonate resin from the surface. Specifically, the organic solvent is one in which at least one good solvent selected from the group consisting of 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, and dioxolane is the main solvent, with methylene chloride being particularly preferred.

[0137] Here, an organic solvent primarily composed of a good solvent means one in which the good solvent preferably accounts for 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 100% or more by weight of the good solvent relative to the total amount of the organic solvent.

[0138] Furthermore, the above organic solvent may contain a poor solvent that does not cause polymer precipitation. Examples of such poor solvents include aliphatic hydrocarbons such as pentane, hexane, and heptane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

[0139] In the recycled polycarbonate resin particles of the present invention, the particle shape is not particularly limited, but from the viewpoint of ease of handling, the average major diameter 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.

[0140] <Viscosity average molecular weight (Mv)> The viscosity-average molecular weight of the recycled polycarbonate resin particles of the present invention is preferably 12,500 to 32,000, more preferably 16,000 to 28,000, and even more preferably 18,000 to 26,000. Polycarbonate resins with a viscosity-average molecular weight below the lower limit may not yield good mechanical properties. On the other hand, resin compositions obtained from polycarbonate resins with a viscosity-average molecular weight exceeding the upper limit may have poor moldability.

[0141] <Oligomer quantity> In the present invention, the oligomer content of the recycled polycarbonate resin particles is preferably 3.0% or less, more preferably 2.7% or less, even more preferably 1.4% or less, and particularly preferably 0.8% or less. Within these ranges, the impact resistance of the molded article obtained from the recycled polycarbonate resin particles is good, which is preferable.

[0142] In this invention, the amount of oligomers is calculated by dissolving 50 mg of the sample in 5 ml of chloroform, introducing 20 μl into a GPC instrument under the following conditions, and determining the ratio (%) of the peak area of ​​oligomer components (number-average molecular weight less than 6,000 in polystyrene equivalent) observed after a retention time of 7.5 min on the GPC chart to the total peak area, and is expressed as area %. This includes monomers, oligomers, additives, and their modified products. (Measurement conditions) Equipment: Waters Co., Ltd. GPC system (Waters2695) Column: TSKgel SuperH3000 manufactured by Tosoh Corporation Flow rate: 0.6mL / min Detector: Waters2487 manufactured by Tosoh Corporation Detection conditions: UV254nm Column temperature: 40.0℃ Standard material: TSK standard polystyrene Eluent: Chloroform

[0143] <Additive amount> In the recycled polycarbonate resin particles of the present invention, the reduction in the residual amounts of various additives (ultraviolet absorbers, heat stabilizers, mold release agents, colorants) is preferable because it makes it easier to prepare materials suitable for various applications when reusing the recycled polycarbonate resin particles.

[0144] The recycled polycarbonate resin particles of the present invention preferably contain 10,000 ppm or less of additives (total amount of UV absorber, heat stabilizer, mold release agent, and colorant), more preferably 8,000 ppm or less, even more preferably 6,000 ppm or less, particularly preferably 5,000 ppm or less, and most preferably 4,500 ppm or less. The amount of each additive (UV absorber, mold release agent, heat stabilizer, and colorant) in the recycled polycarbonate resin particles of the present invention is determined by dissolving the obtained recycled polycarbonate resin particles in dichloromethane, extracting the low molecular weight components by poor solvent precipitation using hexane, and then using a JEOL Ltd. JMN-ECZ400S to extract the extract. 1 The 1H-NMR spectra were measured, and the amount of each additive (UV absorber, mold release agent, heat stabilizer, colorant) was calculated from the integrated values ​​of the peaks originating from each additive.

[0145] Furthermore, the recycled polycarbonate resin particles of the present invention preferably contain a total amount of benzotriazole-based ultraviolet absorbers with a molecular weight of 1000 or less of 5000 ppm or less, more preferably 1000 ppm or less, even more preferably 500 ppm or less, and particularly preferably 300 ppm or less. If a large amount of low molecular weight benzotriazole-based ultraviolet absorbers or their modified products remain, molding defects such as mold contamination and deterioration of the color of the molded sheet are likely to occur.

[0146] Furthermore, due to the ease of adjusting the thermal stability, the recycled polycarbonate resin particles of the present invention preferably have a residual amount of thermal stabilizer of 5000 ppm or less, more preferably 1000 ppm or less, and particularly preferably 500 ppm or less.

[0147] Furthermore, in order to facilitate adjustment of the release properties, the recycled polycarbonate resin particles of the present invention preferably have a residual release agent amount of 5000 ppm or less, more preferably 1000 ppm or less, even more preferably 500 ppm or less, and particularly preferably 300 ppm or less.

[0148] The recycled polycarbonate resin particles of the present invention preferably have a residual colorant content of 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, due to the ease of adjusting the hue.

[0149] <Number of foreign objects> The recycled polycarbonate resin particles of the present invention preferably have a number of insoluble foreign matter particles in methylene chloride collected with a nylon mesh with a mesh size of 20 μm, of which 1500 or fewer, 1300 or fewer, 1100 or fewer, 1000 or fewer, 900 or fewer, 800 or fewer, 700 or fewer, 600 or fewer, 500 or fewer, 400 or fewer, 300 or fewer, or 200 or fewer per 50 g of recycled polycarbonate resin particles. Within the above range, the transparency and appearance of the molded sheet obtained using the recycled polycarbonate resin particles are good.

[0150] The number of foreign particles in this invention was determined by dissolving 50g of the obtained recycled polycarbonate resin particles in dichloromethane, filtering it through a nylon mesh cloth with a mesh opening of 20μm, and then imaging and measuring the number of foreign particles remaining on the nylon mesh cloth using an EDS (Oxford Instruments X-MaxN20) and analysis software (Oxford Instruments AZtec) attached to a SEM (Hitachi High-Tech SU3900).

[0151] <Amount of residual solvent> The recycled polycarbonate resin particles of the present invention preferably have a residual solvent content of 500 ppm or less, more preferably 300 ppm or less, and even more preferably 100 ppm or less, as measured by the HS-GC / MS method. If the residual solvent content exceeds 500 ppm, it may cause corrosion of the equipment due to volatile gases during molding, as well as a decrease in impact resistance, etc.

[0152] <Additive composition> The recycled polycarbonate resin particles of the present invention may be further modified and improved by adding appropriate heat stabilizers, antioxidants, mold release agents (such as fatty acid esters), weathering agents (ultraviolet absorbers), nucleating agents, lubricants, plasticizers, antistatic agents, thickening agents, antibacterial agents, colorants (pigments, dyes), fillers, reinforcing agents, polymers such as other resins and rubbers, flame retardants, etc., to the extent that the properties of the present invention are not impaired. The amount of these additives added is the same as the amount of additives added to the recycled polycarbonate resin (raw material) described above.

[0153] <Polycarbonate resin composition> The recycled polycarbonate resin particles of the present invention are originally from solution b * It can be used as a polycarbonate resin composition by blending recycled polycarbonate resin particles derived from recycled polycarbonate resin molded products that have not yellowed or deteriorated and have a value of 0.7 or less, or with virgin polycarbonate resin.

[0154] <Blending ratio> In a polycarbonate resin composition, the recycled polycarbonate resin particles of the present invention are present in amounts of 5-100% by weight, 10-100% by weight, 20-100% by weight, 30-100% by weight, 40-100% by weight, 50-100% by weight, and solution b. *Recycled polycarbonate resin particles derived from a recycled polycarbonate resin molded product with a yellowness deterioration value of 0.7 or less can be used by blending them in ratios of 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, 0 to 50% by weight, and virgin polycarbonate resin in ratios of 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, 0 to 50% by weight. Solution b * Examples of the recycled polycarbonate resin particles derived from a recycled polycarbonate resin molded product with a yellowness deterioration value of 0.7 or less include post-industrial materials and the like.

[0155] <Hue> In the above polycarbonate resin composition, the hue (b * ) of a molded product (thickness 2 mmt) formed from the polycarbonate resin composition, instead of the recycled polycarbonate resin particles of the present invention, is solution b * Compared with the hue (b * ) of a molded product of a polycarbonate resin composition using recycled polycarbonate resin particles obtained without removing the surface layer of a recycled polycarbonate resin molded product with a yellowness deterioration value of 0.8 to 5.0, although it depends on the blending ratio, it preferably shows a Δb * value that is 0.5 to 20 lower, and more preferably shows a Δb * value that is 1 to 15 lower. Also, although it depends on the blending ratio, it preferably shows a ΔL * value that is 0.1 to 10 higher, and more preferably shows a ΔL * value that is 1 to 5 higher.

[0156] <Molded product> To produce a molded product made of the polycarbonate resin composition of the present invention, any method can be adopted. For example, after kneading the polycarbonate resin composition with an extruder, Banbury mixer or roll, etc., it can be molded by a conventionally known method such as injection molding, extrusion molding or compression molding to obtain a molded product.

Examples

[0157] Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited thereto as long as it does not exceed the gist thereof. The physical property evaluations of the examples and comparative examples were conducted according to the following methods.

[0158] <Solution b * Value> 1 g of the polycarbonate resin was dissolved in 5 ml of methylene chloride, filtered through a PTFE filter with an aperture of 0.22 μm, and then the CIE1976 (L * a * b * ) color system values were measured using an ultraviolet-visible-infrared spectrophotometer V-770DS (manufactured by JASCO Corporation).

[0159] <Viscosity average molecular weight (Mv)> The viscosity average molecular weight (Mv) was determined from the specific viscosity (η SP ) of a solution prepared by dissolving 0.7 g of the polycarbonate in 100 ml of methylene chloride at 20°C using an Ostwald viscometer, Specific viscosity (η SP ) = (t - t0) / t0 [t0 is the dropping time of methylene chloride, t is the dropping time of the sample solution] The viscosity average molecular weight (Mv) was calculated from the obtained specific viscosity (η SP ) 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

[0160] <Number of foreign matters> 50 g of the obtained recycled polycarbonate resin particles were dissolved in dichloromethane, filtered through a nylon mesh cloth with an aperture of 20 μm, and the number of foreign matters remaining on the nylon mesh cloth was imaged and measured using a SEM (SU3900 manufactured by Hitachi High-Tech) equipped with an EDS (X-MaxN20 manufactured by Oxford Instruments) and analysis software (AZtec manufactured by Oxford Instruments).

[0161] <Oligomer quantity> The amount of oligomers was measured using GPC by the following method. 50 mg of the obtained recycled polycarbonate resin particles were dissolved in 5 mL of chloroform, and 20 μl was introduced into a GPC instrument set to the following conditions for measurement. The ratio (%) of the peak area of ​​oligomer components (number-average molecular weight less than 6,000 in polystyrene equivalent) observed after a retention time of 7.5 min in the GPC chart obtained by the above measurement method to the total peak area was calculated and expressed as area %. (Measurement conditions) Equipment: Waters Co., Ltd. GPC system (Waters2695) Column: TSKgel SuperH3000 manufactured by Tosoh Corporation Flow rate: 0.6mL / min Detector: Waters2487 manufactured by Tosoh Corporation Detection conditions: UV254nm Column temperature: 40.0℃ Standard material: TSK standard polystyrene Eluent: Chloroform

[0162] <Additive amount> The obtained recycled polycarbonate resin particles were dissolved in dichloromethane, and the low molecular weight components were extracted by poor solvent precipitation using hexane. Then, the extract was processed using a JEOL Ltd. JMN-ECZ400S. 1 The 1H-NMR spectra were measured, and the total amount of each additive (UV absorber, mold release agent, heat stabilizer, colorant) was calculated from the integrated values ​​of the peaks originating from each additive.

[0163] <Amount of residual solvent> Residual solvent content was measured using the HS-GC / MS method (HS autosampler: Perkin Elmer Turbo Matrix 40, GC: Agilent Technologies 8890 GC system, MS: Agilent Technologies 5977B Inert Plus GC / MSD). 0.1 g of recycled polycarbonate resin particles and 3 mL of N-methylpyrrolidone were weighed and sealed in a headspace sampler vial. After stirring and dissolving with a mix rotor for 60 min, the mixture was measured in SIM mode using HS-GC / MS with heating at 120°C for 60 min. Dichloromethane and acetone were measured using standard samples, and calibration curves were created for peak area percentages and content to calculate the content.

[0164] <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 mesh sizes of 4.75 mm, 2.00 mm, 3.35 mm, 1.40 mm, 1.00 mm, 710 μm, 500 μm, 300 μm, 212 μm, 180 μm, and 106 μm. After sieving, a particle size distribution graph of cumulative sieve percentage based on weight was created, and the particle size at which the cumulative weight reached 50% was determined and taken as the average particle size.

[0165] <Optical properties> The obtained recycled polycarbonate resin particles were placed in a small twin-screw mixer (Xplore Instruments, model: MC15HT), mixed for 2 minutes at a barrel temperature of 280°C and a screw rotation speed of 100 rpm, and then molded in an attached injection molding machine (Xplore Instruments, model: IM12) at a cylinder temperature of 280°C and a mold temperature of 90°C to obtain a molded plate with a thickness of 2 mmt. Using the resulting molded plate, the total light transmittance (TT), haze, and L were measured using the COH 400 color and turbidity simultaneous measuring instrument (D65 light source, 10° field of view) manufactured by Nippon Denshoku Industries Co., Ltd. * a * , b * We measured it.

[0166] [Example 1-1] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) * A piece of recycled polycarbonate resin (2.3g, 300g, 3mm thick) was cut into pieces approximately 5-10cm in size using a cutting machine, then placed in a 5L beaker with a lid, and 3L of methylene chloride was added. After immersion for 3 minutes at room temperature, the molded product was removed and air-dried at room temperature for 16 hours, followed by drying at 120°C for 16 hours. The dried molded product of recycled polycarbonate resin was then crushed at room temperature using a cutter mill to obtain crushed recycled polycarbonate resin (average particle size 1.8mm).

[0167] 200g of the obtained pulverized recycled polycarbonate resin was dissolved in 1800g of methylene chloride and filtered through a 1μm mesh filter. The filtered recycled polycarbonate resin solution and an alkaline aqueous solution (1200g of pure water, 15.1g of NaOH) were placed in a 5L flask, stirred, and after separation, the organic phase was recovered. 1200g of pure water was added to the recovered recycled polycarbonate resin solution for washing, and this process of separating and recovering the organic phase was repeated twice until the aqueous phase became neutral. The washed recycled polycarbonate resin solution and an acid (1200g of pure water, 16.88g of concentrated hydrochloric acid (35-37%)) were placed in a 5L flask, stirred, and after separation, the organic phase was recovered. The recovered recycled polycarbonate resin solution was washed with 1200g of pure water, and after liquid-liquid separation, the organic phase was recovered. This process was repeated twice until the electrical conductivity of the aqueous phase was 10 μS / cm or less. The resulting recycled polycarbonate resin solution was immersed in 80°C hot water to remove methylene chloride, and after pulverization, it was dried at 120°C for 16 hours to obtain recycled polycarbonate resin particles (RPC-1). Solution b of the obtained recycled polycarbonate resin particles (RPC-1) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0168] [Examples 1-2] Recycled polycarbonate resin particles (RPC-2) were obtained in the same manner as in Example 1-1, except that the initial contact time with methylene chloride was 1 minute (1 minute immersion). Solution b of the obtained recycled polycarbonate resin particles (RPC-2) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0169] [Examples 1-3] Similar to Example 1-1, recycled polycarbonate resin molded product (solution b) of yellowed and deteriorated used building material polycarbonate sheet material * The surface layer of a sample (value 2.3, 300g, thickness 3mm) was removed by contact with a solvent, and the sample was pulverized to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm).

[0170] 200g of the obtained recycled polycarbonate resin pulverized product and acid (1200g of pure water, 16.88g of concentrated hydrochloric acid (35-37%)) were placed in a 3L flask, stirred at room temperature for 30 minutes, filtered, and the recycled polycarbonate resin pulverized product was recovered. The recovered recycled polycarbonate resin pulverized product and alkaline aqueous solution (1200g of pure water, 15.1g of NaOH) were placed in a 3L flask, stirred at room temperature for 30 minutes, filtered, and the recycled polycarbonate resin pulverized product was recovered. The recovered recycled polycarbonate resin pulverized product and brine (1200g of pure water, NaCl 22.1g of recycled polycarbonate resin was placed in a 3L flask, stirred at room temperature for 30 minutes, filtered, and the recycled polycarbonate resin pulverized product was recovered. The recovered recycled polycarbonate resin pulverized product and 1200g of pure water were placed in a 3L flask, stirred at room temperature for 30 minutes, filtered, and the polycarbonate resin pulverized product was recovered. The mixture was then dried at 120°C for 16 hours to obtain recycled polycarbonate resin particles (RPC-3). Solution b of the obtained recycled polycarbonate resin particles (RPC-3) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0171] [Examples 1-4] Similar to Example 1-1, recycled polycarbonate resin molded product (solution b) of yellowed and deteriorated used building material polycarbonate sheet material * The surface layer of a sample (value 2.3, 300g, thickness 3mm) was removed by contact with a solvent, and the sample was pulverized to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm).

[0172] 200 g of the obtained pulverized recycled polycarbonate resin was dissolved in 1800 g of methylene chloride, filtered through a 1 μm mesh filter, and the filtered recycled polycarbonate resin solution was placed in 80°C hot water to remove the methylene chloride. After pulverization, it was dried at 120°C for 16 hours to obtain recycled polycarbonate resin particles (RPC-4). Solution b of the obtained recycled polycarbonate resin particles (RPC-4) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0173] [Examples 1-5] Similar to Example 1-1, recycled polycarbonate resin molded product (solution b) of yellowed and deteriorated used building material polycarbonate sheet material * The surface layer of a sample (value 2.3, 300g, thickness 3mm) was removed by contact with a solvent, and the sample was pulverized to obtain recycled polycarbonate resin pulverized product (RPC-5, average particle size 1.8mm). Solution b of the obtained recycled polycarbonate resin particles (RPC-5) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0174] [Examples 1-6] Recycled polycarbonate resin particles (RPC-6) were obtained in the same manner as in Example 1-1, except that they were immersed in tetrahydrofuran for 10 minutes. Solution b of the obtained recycled polycarbonate resin particles (RPC-6) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0175] [Examples 1-7] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) * A piece of recycled polycarbonate resin (2.3g, 300g, 3mm thick) was cut into pieces approximately 5-10cm in size using a cutting machine, then placed in a 5L beaker with a lid, and 3L of methylene chloride was added. After immersion for 3 minutes at room temperature, the molded product was removed and air-dried at room temperature for 16 hours, followed by drying at 120°C for 16 hours. The dried molded product of recycled polycarbonate resin was then crushed at room temperature using a cutter mill to obtain crushed recycled polycarbonate resin (average particle size 1.8mm).

[0176] 200g of the obtained pulverized recycled polycarbonate resin was dissolved in 1800g of methylene chloride and filtered through a 1μm mesh filter. The filtered recycled polycarbonate resin solution and an alkaline aqueous solution (1200g of pure water, 15.1g of NaOH) were placed in a 5L flask, stirred, and after separation, the organic phase was recovered. 1200g of pure water was added to the recovered recycled polycarbonate resin solution for washing, and this process of separating and recovering the organic phase was repeated twice until the aqueous phase became neutral. The washed recycled polycarbonate resin solution and an acid (1200g of pure water, 16.88g of concentrated hydrochloric acid (35-37%)) were placed in a 5L flask, stirred, and after separation, the organic phase was recovered. The recovered recycled polycarbonate resin solution was washed with 1200g of pure water, and after liquid-liquid separation, the organic phase was recovered. This process was repeated twice until the electrical conductivity of the aqueous phase was 10 μS / cm or less. The obtained recycled polycarbonate resin solution was placed in 80°C hot water to remove methylene chloride, pulverized, and dried at 120°C for 16 hours to obtain recycled polycarbonate resin particles. Furthermore, the obtained recycled polycarbonate resin particles and 400 mL of acetone were placed in a 1 L flask, stirred at 40°C for 6 hours, the acetone was filtered off, and the mixture was dried at 120°C to obtain recycled polycarbonate resin particles (RPC-7). Solution b of the obtained recycled polycarbonate resin particles (RPC-7) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0177] [Examples 1-8 to 10] Initial solution b as described in Table 1 * Recycled polycarbonate resin particles (RPC-8~10) were obtained in the same manner as in Example 1-1, except that recycled polycarbonate resin molded products (300g) of used building material polycarbonate sheet material were used and the stirring and dissolution operations were carried out for the time, as shown in Table 1. Solution b of the obtained recycled polycarbonate resin particles (RPC-8~10) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0178] [Reference example 1-1] Recycled polycarbonate resin molded products from used building material polycarbonate sheets that have not yellowed or deteriorated (Solution b) * A 0.2g, 300g, 3mm thick sample was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm). The obtained recycled polycarbonate resin pulverized product was subjected to the same treatment as in Example 1-1 to obtain recycled polycarbonate resin particles (RPC-11). Solution b of the obtained recycled polycarbonate resin particles (RPC-11) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0179] [Reference example 1-2] Recycled polycarbonate resin molded products from used building material polycarbonate sheets that have not yellowed or deteriorated (Solution b) * A 0.2g, 300g, 3mm thick sample was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm). The obtained recycled polycarbonate resin pulverized product was subjected to the same treatment as in Examples 1-4 to obtain recycled polycarbonate resin particles (RPC-12). Solution b of the obtained recycled polycarbonate resin particles (RPC-12) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0180] [Reference example 1-3] Recycled polycarbonate resin molded products from used building material polycarbonate sheets that have not yellowed or deteriorated (Solution b) * A 0.2g, 300g, 3mm thick piece was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm), which was designated as recycled polycarbonate resin particles (RPC-13). Solution b of the obtained recycled polycarbonate resin particles (RPC-13) * The following were evaluated: viscosity-average molecular weight, oligomer content, additive content, number of foreign substances, and residual solvent content.

[0181] [Comparative Example 1-1] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) * A 2.3g, 300g, 3mm thick sample was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm). The obtained recycled polycarbonate resin pulverized product was subjected to the same treatment as in Example 1-1 to obtain recycled polycarbonate resin particles (RPC-14). Solution b of the obtained recycled polycarbonate resin particles (RPC-14) * The following were evaluated: viscosity-average molecular weight, number of foreign particles, amount of oligomers, amount of additives, and amount of residual solvent.

[0182] [Comparative Example 1-2] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) *A 2.3g, 300g, 3mm thick sample was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm). The obtained recycled polycarbonate resin pulverized product was subjected to the same treatment as in Examples 1-3 to obtain recycled polycarbonate resin particles (RPC-15). Solution b of the obtained recycled polycarbonate resin particles (RPC-15) * The following were evaluated: viscosity-average molecular weight, number of foreign particles, amount of oligomers, amount of additives, and amount of residual solvent.

[0183] [Comparative Examples 1-3] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) * A 2.3g, 300g, 3mm thick sample was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm). The obtained recycled polycarbonate resin pulverized product was subjected to the same treatment as in Examples 1-4 to obtain recycled polycarbonate resin particles (RPC-16). Solution b of the obtained recycled polycarbonate resin particles (RPC-16) * The following were evaluated: viscosity-average molecular weight, number of foreign particles, amount of oligomers, amount of additives, and amount of residual solvent.

[0184] [Comparative Examples 1-4] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) * A 2.3g (300g, 3mm thick) material was cut into pieces approximately 5-10cm in size using a cutting machine, and then crushed at room temperature using a cutter mill to obtain recycled polycarbonate resin pulverized product (average particle size 1.8mm), which was designated as recycled polycarbonate resin particles (RPC-17). Solution b of the obtained recycled polycarbonate resin particles (RPC-17) * The following were evaluated: viscosity-average molecular weight, number of foreign particles, amount of oligomers, amount of additives, and amount of residual solvent.

[0185] [Comparative Examples 1-5] Recycled polycarbonate resin particles (RPC-18) were obtained in the same manner as in Example 1, except that they were immersed in methylene chloride for 30 seconds. Solution b of the obtained recycled polycarbonate resin particles (RPC-18) * The following were evaluated: viscosity-average molecular weight, number of foreign particles, amount of oligomers, amount of additives, and amount of residual solvent.

[0186] [Comparative Examples 1-6] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) * A piece of recycled polycarbonate resin (2.3g, 300g, 3mm thick) was cut into pieces approximately 5-10cm in size using a cutting machine, then placed in a 5L beaker with a lid, and 3L of acetone was added. After immersion at room temperature for 3 hours, the molded product was removed and air-dried at room temperature for 16 hours, followed by drying at 120°C for 16 hours. The dried molded product of recycled polycarbonate resin was then crushed at room temperature using a cutter mill to obtain crushed recycled polycarbonate resin (average particle size 1.8mm). The obtained recycled polycarbonate resin pulverized product was subjected to the same treatment as in Example 1-1 to obtain recycled polycarbonate resin particles (RPC-19). Solution b of the obtained recycled polycarbonate resin particles (RPC-19) * The following were evaluated: viscosity-average molecular weight, number of foreign particles, amount of oligomers, amount of additives, and amount of residual solvent.

[0187] [Comparative Examples 1-7] Recycled polycarbonate resin molded products from yellowed and deteriorated used building material polycarbonate sheets (solution b) *After cutting a value of 2.3, 300 g, and a thickness of 3 mm into a size of about 5 to 10 cm using a cutting machine, it was put into a beaker with a 5 L lid, and 3 L of acetone was added. After immersing for 3 hours at room temperature, the recycled polycarbonate resin molded product was taken out and naturally dried at room temperature for 16 hours, and then dried at 120 °C for 16 hours. The dried recycled polycarbonate resin molded product was pulverized with a cutter mill at room temperature to obtain a recycled polycarbonate resin pulverized product (average particle size 1.8 mm). Using the obtained recycled polycarbonate resin pulverized product, the same treatment as in Examples 1-5 was carried out to obtain recycled polycarbonate resin particles (RPC-20). Solution b of the obtained recycled polycarbonate resin particles (RPC-20) * The value, viscosity average molecular weight, number of foreign substances, oligomer amount, additive amount, and residual solvent amount were evaluated.

[0188] [Comparative Examples 1-8, 9] Except for immersing in acetone under the conditions described in Table 1, the same treatment as in Comparative Examples 1-7 was carried out to obtain recycled polycarbonate resin particles (RPC-21, 22).

[0189] [Reference Examples 1-4] Solution b of virgin polycarbonate resin particles (Panlite L-1250WP manufactured by Teijin Limited) (PC-1) * The value, viscosity average molecular weight, number of foreign substances, and residual solvent amount were evaluated.

[0190] [Examples 2-1 to 2-12, Reference Examples 2-1 to 2-4, Comparative Examples 2-1 to 2-7] The recycled polycarbonate resin particles were blended so as to have the weight ratios shown in Tables 3 to 7, and the optical properties were evaluated.

[0191]

Table 1

[0192]

Table 2

[0193]

Table 3

[0194]

Table 4

[0195]

Table 5

[0196]

Table 6

[0197]

Table 7

[0198] As is clear from the comparison between Example 1-1 and Comparative Example 1-1 etc., the recycled polycarbonate resin particles obtained by polishing the surface of the recycled polycarbonate material that has been yellowed and deteriorated have a b * value that has decreased significantly and can have a hue almost equivalent to that of virgin polycarbonate material. Also, it can be seen that by reducing foreign substances and impurities through dissolution / filtration treatment and washing treatment, or by mixing with virgin polycarbonate material, the heat resistance (molded hue) and transparency are further improved.

Industrial Applicability

[0199] The recycled polycarbonate resin particles of the present invention have a significantly improved hue by removing the surface deterioration layer, and further, by reducing foreign substances and impurities or mixing with virgin polycarbonate and using them, they can be widely used as a recycled material excellent in heat resistance (hue after molding) and transparency, and are suitably used in a wide variety of applications where virgin polycarbonate resin is used.

Claims

1. solution b ＊ A method for obtaining recycled polycarbonate resin particles from which the yellowed and deteriorated layer has been removed from a yellowed and deteriorated recycled polycarbonate resin molded product having a value of 0.8 to 5.0, the method for producing recycled polycarbonate resin particles comprising the following steps (I) or (II). (I) (A-1) The surface layer of the recycled polycarbonate resin molded product is removed by contacting it with an organic solvent whose main solvent is a good solvent for polycarbonate resin, and solution b ＊ (B-1) A step to obtain a molded product with improved hue until the value is -0.3 to 0.7 (organic solvent contact treatment step) and (B-1) A step to obtain recycled polycarbonate resin particles by crushing the molded product obtained in step A-1 (crushing treatment step) (II) (B-2) A process to obtain a pulverized product by crushing a recycled polycarbonate resin molded product (crushing process) and (A-2) The surface layer of the pulverized product obtained in the B-2 process is removed by contacting it with an organic solvent mainly composed of a good solvent for polycarbonate resin, and solution b ＊ A process to obtain recycled polycarbonate resin particles with improved hue until the value is between -0.3 and 0.7 (organic solvent contact treatment process).

2. Furthermore, the method for producing recycled polycarbonate resin particles according to claim 1, further comprising (C) a step of dissolving recycled polycarbonate resin particles in a halogenated hydrocarbon solvent, filtering the resin solution obtained, and then removing the halogenated hydrocarbon solvent to produce recycled polycarbonate resin particles (dissolution, filtration, and granulation step).

3. Furthermore, the method for producing recycled polycarbonate resin particles according to claim 1, comprising (D) a step of washing the resin solution obtained by dissolving recycled polycarbonate resin particles in a halogenated hydrocarbon solvent with one or more of water, alkali, acid, and brine (washing step).

4. Recycled polycarbonate resin particles obtained by the manufacturing method described in claim 1 are further given a solubility parameter of 16 to 30 MPa. ０．５ A method for producing recycled polycarbonate resin particles according to claim 1, comprising a step of contacting the particles with an organic solvent for 5 minutes to 10 hours (solvent extraction treatment step).

5. A method for producing recycled polycarbonate resin particles according to claim 1, wherein the organic solvent is an organic solvent whose main solvent is at least one good solvent for polycarbonate resin selected from the group consisting of 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, and dioxolane.

6. (1) 5 to 100% by weight of recycled polycarbonate resin particles obtained by the manufacturing method described in claim 1, and (2) solution b, relative to the total weight of the polycarbonate resin in the polycarbonate resin composition. ＊ A polycarbonate resin composition comprising (3) 0 to 95% by weight of recycled polycarbonate resin particles derived from recycled polycarbonate resin molded products that have not yellowed or deteriorated and have a value of 0.7 or less, and (3) 0 to 95% by weight of virgin polycarbonate resin.

7. Based on the total weight of the polycarbonate resin in the polycarbonate resin composition, (1) 5 to 100% by weight of recycled polycarbonate resin particles obtained by the production method according to claim 1, (2) solution b ＊ 0 to 95% by weight of recycled polycarbonate resin particles derived from a non-yellowing and non-degraded recycled polycarbonate resin molded product with a value of 0.7 or less, and (3) 0 to 95% by weight of virgin polycarbonate resin, which is a polycarbonate resin composition, and the hue (b ＊ ) of the molded product of the polycarbonate resin composition is such that the recycled polycarbonate resin particles obtained without removing the surface layer of a yellowing and degraded recycled polycarbonate resin molded product with a solution b ＊ value of 0.8 to 5.0 is used instead of (1) the recycled polycarbonate resin particles, and the hue (b ＊ ) of the molded product of the polycarbonate resin composition is 0.5 to 20 lower in Δb ＊ value compared to that of the molded product of the polycarbonate resin composition.

8. Solution b obtained by contacting the surface layer with an organic solvent primarily composed of polycarbonate resin, which removes the surface layer. ＊ Recycled polycarbonate resin particles with a value between -0.3 and 0.

7.

9. The recycled polycarbonate resin particles according to claim 8, wherein the organic solvent is an organic solvent whose main solvent is at least one good solvent for polycarbonate resin selected from the group consisting of 1,1,2,2-tetrachloroethane, methylene chloride, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, and dioxolane.

10. (1) 5 to 100% by weight of recycled polycarbonate resin particles as described in claim 8, and (2) solution b, relative to the total weight of the polycarbonate resin in the polycarbonate resin composition. ＊ A polycarbonate resin composition comprising (3) 0 to 95% by weight of recycled polycarbonate resin particles derived from recycled polycarbonate resin molded products that have not yellowed or deteriorated and have a value of 0.7 or less, and (3) 0 to 95% by weight of virgin polycarbonate resin.

11. (1) 5 to 100% by weight of recycled polycarbonate resin particles as described in claim 8, and (2) solution b, relative to the total weight of the polycarbonate resin in the polycarbonate resin composition. ＊ A polycarbonate resin composition comprising (3) 0 to 95% by weight of recycled polycarbonate resin particles derived from recycled polycarbonate resin molded articles that have not yellowed or deteriorated and have a value of 0.7 or less, and 0 to 95% by weight of virgin polycarbonate resin, wherein the hue of the molded article of the polycarbonate resin composition (b ＊ ) is solution b ＊ (1) The hue (b) of a molded polycarbonate resin product obtained without removing the surface layer of a yellowed and deteriorated recycled polycarbonate resin molded product with a value of 0.8 to 5.0 was used in place of the recycled polycarbonate resin particles. ＊ ) Compared to Δb, it is 0.5 to 20 lower. ＊ A polycarbonate resin composition showing a value.

12. A molded article formed from the polycarbonate resin composition according to any one of claims 6 to 7 or 10 to 11.

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