Polycarbonate resin composition

Abstract

To provide a polycarbonate resin composition that ensures sufficient melt fluidity even in injection molding, while exhibiting excellent heat resistance, impact resistance, material recyclability, and appearance of the molded product. [Solution] A resin composition comprising 1 to 5 parts by mass of recycled wax (B) per 100 parts by mass of polycarbonate resin (A), wherein the polycarbonate resin (A) has a melt volume flow rate of 5 to 14 cm². 3 A polycarbonate resin composition in which the recycled wax (B) satisfies the following conditions (i) to (iv). (i) Number-average molecular weight (Mn) is between 500 and 8,000. (ii) The ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (molecular weight distribution: Mw / Mn) is 1.0 or greater and less than 4.0. (iii) Melting point (Tm) is between 60°C and 125°C. (iv) Acid value is less than 0.5 mg-KOH / g.

Description

Technical Field

[0001] The present invention relates to a polycarbonate resin composition and an injection molded article thereof.

Background Art

[0002] Polycarbonate resin is a plastic excellent in heat resistance, impact resistance, and transparency, and is widely used in various fields such as the fields of electric and electronic equipment, automobiles, OA equipment, and home appliances. In these fields, polycarbonate resin is used not only for transparent parts but also for colored parts because it is superior in heat resistance and impact resistance to ABS (acrylonitrile-butadiene-styrene terpolymer) and PMMA (polymethyl methacrylate).

[0003] However, polycarbonate resin has poor melt fluidity during molding processing, so there are problems such as deformation of molded products and deterioration of appearance in the manufacture of thin-walled parts and parts with complex shapes.

[0004] Therefore, it is molded by a special molding method such as injection compression molding, but there is a problem that the production speed decreases in these special molding methods. Also, attempts have been made to lower the viscosity and improve the melt fluidity by raising the molding temperature in injection molding or lowering the molecular weight of the polycarbonate resin. However, the former is not only insufficient as a modification effect but also causes thermal degradation, and the latter has problems such as a decrease in heat resistance and mechanical properties.

[0005] [[ID=二十三]] In recent years, from the viewpoint of effective utilization of resources, promotion of material recycling that uses product waste as a raw material has been demanded, and polycarbonate resin has a significant demand for material recycling from its wide range of product fields. However, even in the material recycling of polycarbonate resin, the low melt fluidity is a problem as in the case of virgin resin, and many research and developments have been conducted to reach a usable level.

[0006] Against this backdrop, studies have been conducted to improve the melt-flow properties of polycarbonate resins and the like by adding lubricants. For example, polycarbonate resin compositions have been proposed in which pentaerythritol, linear saturated fatty acids, adipic acid, and fatty acid complex ester wax are added to the polycarbonate resin to improve melt-flow properties and heat resistance (see, for example, Patent Document 1). Polycarbonate resin compositions have been proposed in which oxidative acid-modified polyethylene wax is added to the polycarbonate resin to improve melt-flow properties without worsening heat resistance (see, for example, Patent Document 2). Furthermore, polycarbonate resin compositions have been proposed in which a polyorganosiloxane containing nitrogen-containing organic groups is added to a resin mixture consisting of a specific proportion of polycarbonate resin and polylactic acid to improve melt-flow properties and impact resistance, and the addition of polylactic acid further improves the moisture resistance of the polycarbonate, resulting in improved durability and excellent recyclability (see, for example, Patent Document 3). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-195453 [Patent Document 2] Patent No. 6682534 [Patent Document 3] Japanese Patent Publication No. 2008-37965 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the polycarbonate resin compositions proposed in Patent Documents 1 and 2 had problems because they did not consider maintaining or improving impact resistance. Furthermore, the polycarbonate resin composition proposed in Patent Document 3 added polylactic acid, which has very high hygroscopic properties. When injection molding of polycarbonate resin, which requires very high processing temperatures, the absorbed moisture greatly affects the processing, posing a problem in terms of handling. Moreover, these polycarbonate resin compositions were not considered as injection molding materials that provide fluidity or recyclability.

[0009] Therefore, the present invention aims to solve these problems by providing a polycarbonate resin composition containing a specific recycled wax, thereby providing sufficient melt fluidity during injection molding, excellent heat resistance, impact resistance, and recyclability of the molded product, and reducing warping, which is a defect in the appearance of the molded product. [Means for solving the problem]

[0010] As a result of diligent research to solve the aforementioned problems, the present inventors have found that a resin composition obtained by blending a specific polycarbonate resin with a specific recycled wax in a specific ratio provides sufficient melt fluidity during injection molding, exhibits excellent heat resistance, impact resistance, and recyclability of the molded product, reduces warping which is a defect in the appearance of the molded product, and moreover, improves fluidity compared to when virgin wax is used, suppressing the decrease in heat resistance and impact resistance, thus completing the present invention.

[0011] In other words, the embodiments of the present invention are as follows [1] to [5]. [1] A resin composition comprising 1 to 5 parts by mass of recycled wax (B) per 100 parts by mass of polycarbonate resin (A), wherein the polycarbonate resin (A) has a melt volume flow rate of 5 to 14 cm³ measured at 300°C and a load of 1.2 kg in accordance with JIS K 7210. 3A polycarbonate resin composition comprising a polycarbonate resin of / g, wherein the recycled wax (B) satisfies the following conditions (i) to (iv). (i) The number-average molecular weight (Mn) measured by gel permeation chromatography (GPC) is between 500 and 8,000. (ii) The ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) measured by GPC (molecular weight distribution: Mw / Mn) is 1.0 or greater and less than 4.0. (iii) The melting point (Tm) measured by differential scanning calorimetry (DSC) is between 60°C and 125°C. (iv) Acid value is less than 0.5 mg-KOH / g. [2] The polycarbonate resin composition according to [1], wherein the polycarbonate resin (A) is a recycled polycarbonate resin. [3] The polycarbonate resin composition according to [1], wherein the recycled wax (B) is polyethylene wax obtained by thermal decomposition of post-industrial recycled polyethylene and post-consumer recycled polyethylene. [4] A polycarbonate resin composition according to any one of [1] to [3], for injection molding. [5] An injection-molded article made from a polycarbonate resin composition as described in any of [1] to [3]. [Effects of the Invention]

[0012] The polycarbonate resin composition of the present invention maintains the advantages of polycarbonate, namely its heat resistance and impact resistance, while also providing sufficient melt fluidity during injection molding and reducing defects in the appearance of the resulting molded product. Furthermore, its improved durability results in excellent recyclability. Therefore, it is useful for manufacturing injection-molded polycarbonate resin products. [Modes for carrying out the invention]

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

[0014] One embodiment of the present invention is a polycarbonate resin composition comprising 1 to 5 parts by mass of recycled wax (B) per 100 parts by mass of polycarbonate resin (A), which provides sufficient melt fluidity during injection molding, and the molded product has excellent heat resistance, impact resistance, and recyclability, as well as reducing warping, which is a defect in the appearance of the molded product.

[0015] The polycarbonate resin (A) mentioned above is generally a polymer in which dihydroxy compound residues are linked by carbonate ester bonds, and typically refers to a polymer obtained by reacting a dihydroxy component with a carbonate precursor using interfacial polymerization or melt polymerization.

[0016] The dihydroxy compounds used in this case include 2,2-bis(4-hydroxyphenyl)propane (sometimes called bisphenol A), 2,2-bis((4-hydroxy-3-methyl)phenyl)propane (sometimes called bisphenol C), bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, and 2,2- Examples include bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 9,9-bis((4-hydroxy-3-methyl)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene, isosorbide, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, etc. These may be used individually or in combination of two or more to form a polycarbonate resin, and it is particularly preferable that the polycarbonate resin contains 2,2-bis(4-hydroxyphenyl)propane because it has an excellent balance of heat resistance and impact resistance.

[0017] In addition, examples of the carbonate precursor include carbonyl halide, carbonyl ester, haloformate, etc. Specifically, phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, diphenyl carbonate, dimethyl carbonate, diethyl carbonate, etc. may be mentioned.

[0018] Furthermore, the polycarbonate resin (A) may have a branched structure. Examples of the branching agent include 1,1,1-tris(4-hydroxyphenyl)ethane, α,α’,α’’-tris(4-hydroxyphenyl)-1,3,5-triisopropylbenzene, phloroglucin, trimellitic acid, isatin bis(o-cresol), etc.

[0019] The polycarbonate resin (A) complies with JIS K 7210 and has a melt volume flow rate measured at 300 °C under a load of 1.2 kg of 5 to 14 cm 3 / g. As long as it belongs to this range, it may be a commercially available product. For example, (trade name) Tufflon #2000 (manufactured by Idemitsu Kosan Co., Ltd.), (trade name) Tufflon #2200 (manufactured by Idemitsu Kosan Co., Ltd.), (trade name) Panlite L-1250Y (manufactured by TEIJIN LIMITED), (trade name) Panlite L-1225Y (manufactured by TEIJIN LIMITED), etc. can be mentioned. Here, when the melt volume flow rate is less than 5 cm 3 [[ID=1 2]] / g, the resulting composition not only has a high viscosity, poor melt fluidity and moldability, but is also likely to deteriorate due to excessive heat history required during recycling, resulting in poor recyclability. On the other hand, when the melt volume flow rate exceeds 14 cm 3 / g, not only is the molecular weight low and the impact resistance poor, but it is also likely to cause thermal degradation during recycling.

[0020] The polycarbonate resin (A) may be unused virgin resin or recycled resin obtained by recovering used molded products. That is, the form includes one or more types of resins that are all unused virgin resin, one or more types of resins that are at least one recycled resin, and one or more types of resins that are all recycled resin.

[0021] Polycarbonate resin (A), when using recycled resin, may contain multiple types of resin. In this case, it may contain organic impurities such as wax, adhesives, plasticizers, and antioxidants. On the other hand, it may also contain inorganic impurities such as fillers.

[0022] The recycled wax (B) has a number-average molecular weight (Mn) of 500 to 8,000, preferably 500 to 5,000, as measured by gel permeation chromatography (GPC). If the number-average molecular weight (Mn) is less than 500, the impact resistance of the molded product decreases, and if it exceeds 8,000, the improvement in melt fluidity during injection molding is small and undesirable.

[0023] Recycled wax (B) has a ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (molecular weight distribution: Mw / Mn) of 1.0 or more and less than 4.0, preferably 1.0 or more and less than 3.3, as measured by GPC. If the molecular weight distribution is outside the above range, the impact resistance, moldability, and recyclability of the molded product will be inferior.

[0024] Furthermore, the recycled wax (B) has a melting point of 60°C to 125°C, preferably 70°C to 115°C. If the melting point is outside this range, the fluidity and appearance of the molded product will be inferior.

[0025] Furthermore, the recycled wax (B) has an acid value of less than 0.5 mg KOH / g. Because the acid value is within this range, the highly polar polycarbonate resin (A) and the non-polar recycled wax (B) are mismatched. During injection molding, the interface between the polycarbonate resin (A) and the recycled wax (B) becomes slippery, resulting in improved melt fluidity of the polycarbonate resin composition.

[0026] Next, the manufacturing method for the recycled wax (B) described above will be explained.

[0027] Recycled wax (B) is manufactured by feeding recycled waste plastic into an extruder and thermally decomposing it within the extruder.

[0028] Recycled waste plastics are classified into post-consumer recycled materials (sometimes abbreviated as PCR) and post-industrial recycled materials (sometimes abbreviated as PIR). PCR refers to materials collected or recycled after products have been used and discarded by consumers, while PIR refers to materials collected or recycled as waste generated in the manufacturing process before products reach consumers. The recycled waste plastics are preferably polyethylene resins for both PCR and PIR. Examples of types include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-high molecular weight polyethylene, and mixtures of these waste plastics are also acceptable. Furthermore, the form of the plastic is not limited to pellets or powders; it may also be molded products such as films, sheets, bottles, fibers, pipes, and injection-molded products, as well as their crushed materials. Examples of waste plastics include used products, off-spec products, and discarded products. Among these, waste polyethylene generated in the extrusion lamination manufacturing process is the most preferred. Furthermore, if the waste plastic is a rubber composition, it is acceptable whether the components are dissolved and mixed together, or whether the components are physically mixed together in solid form such as pellets or scraps.

[0029] Recycled waste plastics can be used as is, even if antioxidants have been added during manufacturing or during molding into products such as films. Furthermore, antioxidants can be added during the thermal decomposition reaction to prevent oxidative degradation.

[0030] Extruders are not particularly limited and can include, for example, single-screw extruders, co-rotating twin-screw extruders, anomalous-rotating twin-screw extruders, multi-screw extruders such as four-screw or eight-screw extruders with three or more screws arranged in parallel within the extruder's cylinder, and tandem extruders such as those with two or more extruders connected in series, those arranged in an L-shape by connecting the outlet of one extruder to the inlet of the other, and those arranged in a T-shape by connecting the outlet of one extruder to the side of the other. Furthermore, each extruder constituting the tandem extruder can be a single-screw extruder or a multi-screw extruder with two to eight screws, and two or more of these extruders can be combined to form a tandem extruder. Among these extruders, co-rotating twin-screw extruders, 4- to 8-screw multi-screw extruders, and tandem extruders are preferred because they yield recycled wax (B) of particularly stable quality and exhibit excellent stability in torque and discharge volume during extrusion. It is preferable to install side feeders for introducing the modifying agent in these extruders.

[0031] Furthermore, it is preferable that the extruder be equipped with a vacuum vent to efficiently discharge the low molecular weight gas components that have been thermally decomposed. In addition, it is preferable that the screw length (L) to screw diameter (D) ratio (L / D) be 30 or more, and particularly 40 or more, so that the thermal decomposition of waste plastic can be carried out efficiently and a recycled wax (B) of stable quality can be obtained.

[0032] The conditions for thermal decomposition after supplying waste plastic to the extruder should be appropriately adjusted according to the molecular weight of the desired recycled wax. However, since thermal decomposition can be performed in a short time and the odor of the resulting thermally decomposed wax can be suppressed, for example, the cylinder temperature in the thermal decomposition region can be in the range of 330 to 480°C, more preferably 350 to 460°C, and particularly preferably 380 to 450°C. The residence time in the thermal decomposition region can be in the range of 0.5 to 60 minutes, more preferably 1 to 45 minutes, and particularly preferably 1.5 to 30 minutes.

[0033] Furthermore, to suppress the odor of the resulting recycled wax (B) and to facilitate control of its molecular weight and degree of modification, it is preferable that the inside of the extruder during thermal decomposition be replaced with an inert gas such as hydrogen, helium, argon, nitrogen, or carbon dioxide, and particularly preferable that it be replaced with nitrogen gas. The wax extruded from the extruder can then be made into pellets by methods such as hot cutting, mist cutting, underwater cutting, or by cooling on a steel belt and then cutting.

[0034] Recycled wax (B) can be used in any form, such as pellets, powder, flakes, granules, grains, or paste.

[0035] The above polycarbonate resin composition contains 1 to 5 parts by mass of recycled wax (B) per 100 parts by mass of polycarbonate resin (A), and it is preferable that it contains 1 to 3 parts by mass, considering the balance of impact resistance, moldability, and recyclability. If the amount of recycled wax (B) is less than 1 part by mass, the effect of improving fluidity and the appearance of the molded product will be insufficient. On the other hand, if it exceeds 5 parts by mass, the impact resistance and heat resistance will deteriorate.

[0036] Various molded products can be manufactured from the above-mentioned polycarbonate resin composition by methods such as injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, and foam molding.

[0037] Preferably, the above polycarbonate resin composition is used to produce pelletized molding material by the above melt-kneading molding method, and then these pellets can be used to produce injection-molded products in injection molding and injection compression molding, where melt-flowability, heat resistance, impact resistance, and molded appearance are of utmost importance. The molding temperature is usually appropriately selected within the range of 240 to 320°C, according to the melting point of the polycarbonate resin.

[0038] The above polycarbonate resin composition is useful as a molding material for molded products that become components of electrical and electronic equipment, precision machinery, office equipment, home appliances, optical materials, and the like.

[0039] An injection-molded article according to one aspect of the present invention is obtained by injection molding the above-mentioned polycarbonate resin composition, and examples include office automation equipment such as photocopiers, fax machines, televisions, radios, tape recorders, video decks, personal computers, printers, telephones, information terminals, refrigerators, and microwave ovens, as well as household electrical appliances, housings and various parts for electrical and electronic equipment, and optical lenses used in cameras, etc. [Examples]

[0040] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0041] <Examples of recycled wax production> (1) Evaluation method of recycled wax 1) GPC measurement Equipment: HLC(registered trademark)-8321GPC / HT (Detector: RI method) (Manufactured by Tosoh Corporation) Columns: Use one column (i) and three columns (ii) in series. (i) TSKgel® guardColumuH(HR)(30)HT (7.5mm I.D.) x 7.5cm) (Manufactured by Tosoh Corporation) x 1 piece (ii) TSKgel® GMH(HR)-H(20)HT (7.5mm I.D.) x 30cm) (Manufactured by Tosoh Corporation) x 3 pieces Eluent: 1,2,4-Trichlorobenzene (containing 0.05 wt% BHT) (Purchased from Fujifilm Wako Pure Chemical Corporation) Flow rate: 1.0mL / min Injection volume: 0.3mL Column temperature: 140℃ Temperature: 40°C Sample concentration: 1 mg / mL Calibration curve: A fifth-order approximation curve using standard polystyrene manufactured by Tosoh Corporation. However, the molecular weight was converted to PE-equivalent molecular weight using the Q factor.

[0042] 2) Melting point measurement Measurements were taken in accordance with JIS K7122 (2012).

[0043] The melting point of the recycled wax was measured using differential scanning calorimetry (DSC) with a DSC7000X (Hitachi High-Tech Science). Approximately 10 mg of the sample was sealed in an aluminum pan and heated from -20°C to 200°C at a rate of 10°C / min. The endothermic peak of the resulting curve was identified as the melting point. Prior to this heating measurement, the sample was first heated to approximately 200°C, held for 5 minutes, and then cooled to -20°C at a rate of 20°C / min to unify the thermal history of the sample.

[0044] 3) Measurement of acid value Measurements were taken in accordance with JIS K 2501 under the following conditions.

[0045] Apparatus: 50 mL burette (minimum graduation 0.1 mL), Erlenmeyer flask Reagents: Toluene, methanol, dimethylformamide, pure water, phenolphthalein indicator, N / 20KOH-n-propanol / toluene solution (F=0.9758) Melting conditions: 165℃×30min Reaction conditions: Room temperature × 30 min Sample quantity: approximately 1g [Manufacturing Example 1] A twin-screw extruder with a screw diameter of 11 mm and a screw length-to-screw diameter ratio (L / D) of 40 was used as the extruder. As the waste plastic, used post-industrial recycled (PIR) polyethylene (number average molecular weight 15,000) generated during resin switching in extrusion lamination molding of low-density polyethylene (Petrocene® 205, manufactured by Tosoh Corporation) was used. The polyethylene was crushed to an average particle size of 10 mm or less and its volume was reduced. It was then fed into the main feeder of the extruder at a supply rate of 20 g / hr along with a constant flow rate of nitrogen gas, and thermally decomposed by melting and kneading under conditions where the cylinder temperature in the thermal decomposition zone of the extruder was heated to 450°C and the cooling zone to 200°C. Next, the molten mixture was extruded onto a steel plate placed under a nitrogen atmosphere, cooled, and then crushed to obtain powdered recycled wax. Then, GPC measurements were performed using the obtained recycled wax (B-1), and the results showed a number-average molecular weight (Mn) of 1,500, a molecular weight distribution (Mw / Mn) of 3.0, a melting point (Tm) of 108°C, and an acid value of 0 mg-KOH / g.

[0046] [Manufacturing Example 2] Recycled wax was obtained in the same manner as in Example 1, except that used polyethylene (number average molecular weight 13,000), which is a scrap of laminate film made from low-density polyethylene (Petrocene® 203, manufactured by Tosoh Corporation), was used as waste plastic. The analysis results of the obtained recycled wax (B-2) are shown in Table 1.

[0047] [Manufacturing Example 3] Recycled wax was obtained using the same method as in Production Example 2, except that the waste plastic supply rate was set to 120 g / hr. The analysis results of the obtained recycled wax (B-3) are shown in Table 1.

[0048] [Manufacturing Example 4] PCR wax was obtained in the same manner as in Example 1, except that polyethylene (recovered from waste beverage bottles, specific gravity 0.96, MFR (190°C, 10 min) 0.35) was used as the waste plastic for the PCR material. The analysis results of the obtained PCR wax (B-4) are shown in Table 1.

[0049] [Manufacturing Example 5] PCR wax was obtained in the same manner as in Example 1, except that post-consumer recycled (PCR) polyethylene (recovered from plastic container and packaging waste, containing polypropylene (<0.5%) and polystyrene (<1.3%), and trace amounts of other polymers (<0.03% polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, acrylonitrile-butadiene-styrene terpolymer, polyamide, polyurethane)) was used as waste plastic. The analytical results of the obtained PCR wax (B-5) are shown in Table 1.

[0050] [Table 1]

[0051] <Examples of Polycarbonate Resin Composition Production> (1) Raw materials 1) Polycarbonate resin (A-1): Manufactured by Idemitsu Kosan Co., Ltd., product name: Toughlon A2200 Melt Volume Flow Rate 12cm 3 / 10 minutes (temperature 300℃, load 1.2kg) 2) Recycled resin (A-2): The above polycarbonate resin (A-1) was used to create an injection-molded product according to the preparation of the test piece described in (2)1) below. This product was left in a room with an average temperature of 20°C for one year, and then crushed with a rotary cutter. 3) Recycled wax: Prepared according to the manufacturing example. See Table 1 for resin properties.

[0052] 4) Virgin wax: Manufactured by Mitsui Chemicals, Inc., product name: High Wax 405P.

[0053] See Table 1 for resin properties. (2) Method for evaluating polycarbonate resin compositions 1) Preparation of test specimens Using an injection molding machine MD100Xi2.7 (manufactured by Ube Machinery Corporation), test pieces for the following evaluations were molded using a JIS family mold at a resin temperature of 280°C, a mold temperature of 80°C, an injection speed of 40 mm / s, and a holding pressure of 20 MPa.

[0054] 2) Injection pressure (unit: MPa) The average injection pressure was recorded when 10 test specimens were molded under the above conditions, and this was used as an indicator of melt fluidity.

[0055] 3) Izod impact strength (unit: kJ / m 2 ) Measurements were taken using notched, rectangular test specimens measuring 64 mm x 12.7 mm x 4 mm, in accordance with JIS K7110-1984 "Izod Impact Test Method for Hard Plastics". The measurement temperature was 23°C.

[0056] 4) Temperature of deflection under load Using strip-shaped test pieces measuring 120 mm x 12.7 mm x 4 mm, measurements were taken at a test load of 0.45 MPa in accordance with JIS K7207-1995 "Temperature Test Method for Load Deflection of Rigid Plastics".

[0057] 5) Amount of curvature The amount of warpage was evaluated for test specimens obtained from the family mold. Here, warpage refers to the straight-line distance between the sprue lock at the end of the sprue and the plane when the four gate vertices of the family mold are fixed to the plane.

[0058] Example 1 1 part by mass of recycled wax (B-1) was mixed with 100 parts by mass of polycarbonate resin (A-1), pre-blended in a tumbler mixer, and then melt-kneaded at 250°C using a single-screw extruder to obtain pellets of the polycarbonate resin composition.

[0059] The obtained polycarbonate resin composition pellets were dried at 100°C for 5 hours, and then injection-molded articles were obtained using the test specimen preparation method described above. The results of the evaluation using the injection-molded articles are shown in Table 2.

[0060] Example 2 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 1, except that 3 parts by mass of recycled wax (B-1) were used per 100 parts by mass of polycarbonate resin (A-1). The evaluation results are shown in Table 2.

[0061] Example 3 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 2, except that recycled resin (A-2) was used instead of polycarbonate resin (A-1) and recycled wax (B-2) was used instead of recycled wax (B-1). The evaluation results are shown in Table 2.

[0062] Example 4 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 3, except that 2 parts by mass of recycled wax (B-1) and 1 part by mass of recycled wax (B-2) were used instead of 3 parts by mass of recycled wax (B-2). The evaluation results are shown in Table 2.

[0063] Example 5 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained using the same method as in Example 3, except that recycled wax (B-3) was used instead of recycled wax (B-2). The evaluation results are shown in Table 2.

[0064] Example 6 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 3, except that 1 part by mass of recycled wax (B-4) was used instead of 3 parts by mass of recycled wax (B-2). The evaluation results are shown in Table 2.

[0065] Example 7 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 3, except that 5 parts by mass of recycled wax (B-1) were used instead of 3 parts by mass of recycled wax (B-2). The evaluation results are shown in Table 2.

[0066] [Table 2]

[0067] Comparative Example 1 Pellets and injection-molded articles were obtained using the same method as in Example 1, except that recycled wax (B-1) was not used. The evaluation results are shown in Table 3.

[0068] Comparative Example 2 Polycarbonate resin pellets and injection-molded articles thereof were obtained using the same method as in Example 1, except that recycled wax (B-1) was not used and recycled resin (A-2) was used as the polycarbonate resin (A). The evaluation results are shown in Table 3.

[0069] Comparative Example 3 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 3, except that 10 parts by mass of recycled wax (B-1) were used instead of 3 parts by mass of recycled wax (B-2). The evaluation results are shown in Table 3.

[0070] Comparative Example 4 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained using the same method as in Example 2, except that recycled wax (B-5) was used instead of recycled wax (B-1). The evaluation results are shown in Table 3.

[0071] Comparative Example 5 Pellets of a polycarbonate resin composition and injection-molded articles thereof were obtained by the same method as in Example 2, except that virgin wax (B-6) was used instead of 3 parts by mass of recycled wax (B-2). The evaluation results are shown in Table 3.

[0072] [Table 3] [Industrial applicability]

[0073] The polycarbonate resin composition of the present invention maintains the heat resistance and impact resistance characteristic of polycarbonate while providing sufficient melt fluidity during injection molding, thereby reducing defects in the appearance of the resulting molded product. Furthermore, it offers excellent material recyclability due to improved durability. For this reason, it is useful as a molding material for molded products that become components of electrical and electronic equipment, precision machinery, office equipment, home appliances, optical materials, and the like.

Claims

1. The resin composition contains 1 to 5 parts by mass of recycled wax (B) per 100 parts by mass of polycarbonate resin (A), wherein the polycarbonate resin (A) has a melt volume flow rate of 5 to 14 cm³ measured at 300°C and a load of 1.2 kg in accordance with JIS K 7210. ３ A polycarbonate resin composition comprising a polycarbonate resin of weight / g, wherein the recycled wax (B) satisfies the following conditions (i) to (iv). (i) The number-average molecular weight (Mn) measured by gel permeation chromatography (GPC) is between 500 and 8,000. (ii) The ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) measured by GPC (molecular weight distribution: Mw / Mn) is 1.0 or greater and less than 4.

0. (iii) The melting point (Tm) measured by differential scanning calorimetry (DSC) is between 60°C and 125°C. (iv) Acid value is less than 0.5 mg-KO / g.

2. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin (A) is a recycled polycarbonate resin.

3. The polycarbonate resin composition according to claim 1, wherein the recycled wax (B) is polyethylene wax obtained by thermally decomposing post-industrial recycled polyethylene and post-consumer recycled polyethylene.

4. A polycarbonate resin composition according to any one of claims 1 to 3, for use in injection molding.

5. An injection-molded article comprising the polycarbonate resin composition according to any one of claims 1 to 3.

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