Aromatic polycarbonate resin composition and molded article thereof

Abstract

To provide an aromatic polycarbonate resin composition that is useful as a transparent molded article for outdoor installation and has excellent transparency, hue, weather resistance, and impact resistance, and provide a molded article thereof.SOLUTION: An aromatic polycarbonate resin composition contains, based on 100 pts.wt. of an aromatic polycarbonate resin (A), 2.5-4.0 pts.wt. of a benzotriazole weathering agent (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aromatic polycarbonate resin composition and a molded article thereof. More specifically, the present invention relates to an aromatic polycarbonate resin composition and a molded article thereof that are useful as a transparent molded article for outdoor installation and have excellent transparency, color, weather resistance, and impact resistance. [Background technology]

[0002] In recent years, the effective use of solar energy, the widespread use of lighting fixtures such as LEDs, and the development of wireless infrastructure have led to a further increase in the number of devices installed outdoors. These devices often require cover materials that require transparency, such as transparent or translucent lighting covers for LEDs, organic electroluminescent (EL) light sources, transparent covers for solar panels for photovoltaic power generation, and various meter covers for LCDs, meters, etc., because they require light transmittance and display device visibility. Transparent materials are used for such transparent cover materials, but thermoplastic resins are preferable to glass in terms of ease of processing and lightweight design.

[0003] However, thermoplastic resins typically used are vulnerable to various environmental conditions in outdoor environments, and therefore lack durability in these devices, which are expected to be used for relatively long periods of time. For example, acrylic resin, the most common transparent resin, has low impact resistance and easily cracks. In addition, its poor heat resistance and flame retardancy make it unsuitable for use as a cover for electronic and electrical devices. On the other hand, polycarbonate resins made from bisphenol A have excellent impact resistance and are relatively heat-resistant and flame-retardant among polymeric materials, but they have the problem of yellowing of the surface when exposed to ultraviolet rays outdoors for long periods of time.

[0004] As described above, polycarbonate resins do not have sufficient weather resistance, and for example, their use outdoors or indoors under fluorescent light irradiation has been limited due to discoloration or a decrease in strength of the product. For this reason, various light stabilizers have been used either alone or in combination, and benzotriazole-based ultraviolet absorbers in particular are commonly used because of their relatively high effectiveness.

[0005] Patent Document 1 describes a polycarbonate resin composition with improved weather resistance, in which 0.001 to 5 parts by weight of an alkylidenebis(benzotriazolylphenol) compound represented by a specific structure is added to 100 parts by weight of the polycarbonate resin composition. However, this document merely shows that the addition of the ultraviolet absorber reduces the change in yellowness index (ΔYI) before and after ultraviolet irradiation with a high-pressure mercury lamp, and makes no mention of weather resistance or impact resistance in long-term tests.

[0006] Patent Document 2 describes eyeglass lenses formed from a resin composition containing 100 parts by weight of polycarbonate resin and 0.5 to 3 parts by weight of an ultraviolet absorber having two benzotriazolylphenol groups, but does not mention anything about transparent molded articles for outdoor use. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 6-51840 [Patent Document 2] Japanese Patent Application Publication No. 9-291205 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides an aromatic polycarbonate resin composition having excellent transparency, color, weather resistance and impact resistance, which is useful as a transparent molded article for outdoor installation, and a molded article thereof. [Means for solving the problem]

[0009] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that by blending a benzotriazole-based weather resistance agent in a specific ratio with an aromatic polycarbonate resin, it is possible to obtain an aromatic polycarbonate resin composition that is useful as a transparent molded article for outdoor installation and that has good transparency, hue, weather resistance, and impact resistance, and a molded article formed from the resin composition, and thus the above-mentioned objects can be achieved, thereby completing the present invention. That is, according to the present invention, the following (Configuration 1) to (Configuration 9) are provided.

[0010] (Configuration 1) An aromatic polycarbonate resin composition containing 2.5 to 4.0 parts by weight of a benzotriazole-based weather resistance agent (B) based on 100 parts by weight of an aromatic polycarbonate resin (A). (Configuration 2) The resin composition according to configuration 1, wherein the benzotriazole-based weather resistance agent (B) is represented by the following formula (I):

[0011] [ka]

[0012] (Configuration 3) 3. The aromatic polycarbonate resin composition according to claim 1 or 2, which contains 0.001 to 0.5 parts by weight of a heat stabilizer (C) based on 100 parts by weight of the aromatic polycarbonate resin (A). (Configuration 4) 4. The aromatic polycarbonate resin composition according to any one of configurations 1 to 3, comprising 0.05 to 0.5 parts by weight of a mold release agent (D) per 100 parts by weight of the aromatic polycarbonate resin (A). (Configuration 5) 5. The aromatic polycarbonate resin composition according to any one of aspects 1 to 4, which has a Charpy impact strength of 10 or more. (Configuration 6) 6. The aromatic polycarbonate resin composition according to any one of aspects 1 to 5, having a hue YI of 7.0 or less. (Configuration 7) 7. The aromatic polycarbonate resin composition according to any one of aspects 1 to 6, wherein the ΔYI after 1000 hours of treatment in a sunshine weather meter is 2.5 or less. (Configuration 8) A molded article formed from the aromatic polycarbonate resin composition according to any one of aspects 1 to 7. (Configuration 9) 9. The molded article according to configuration 8, which is a transparent molded article for outdoor installation. [Effects of the Invention]

[0013] The aromatic polycarbonate resin composition of the present invention is excellent in transparency, color, weather resistance, and impact resistance, and is therefore extremely useful as a transparent molded article for outdoor installation. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be described in detail below.

[0015] <Aromatic polycarbonate resin (A)> The aromatic polycarbonate resin used in the present invention is an aromatic polycarbonate resin obtained by reacting a dihydric phenol with a carbonate precursor. Specific examples of the dihydric phenol used herein include bis(hydroxyaryl)alkanes such as 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 2,2-bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane; dihydroxyaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone.

[0016] These dihydric phenols may be used alone or in combination of two or more. Among the dihydric phenols, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is preferably used as the main dihydric phenol component, and particularly, bisphenol A accounts for 70 mol% or more, particularly 80 mol% or more of the total dihydric phenol components. Most preferred is an aromatic polycarbonate resin in which the dihydric phenol component is essentially bisphenol A.

[0017] The basic methods for producing aromatic polycarbonate resins are briefly described below. In the solution method, which uses phosgene as the carbonate precursor, the reaction between a dihydric phenol component and phosgene is typically carried out in the presence of an acid binder and an organic solvent. Examples of acid binders include alkali metal hydroxides such as sodium hydroxide or potassium hydroxide, or amine compounds such as pyridine. Examples of organic solvents include halogenated hydrocarbons such as methylene chloride or chlorobenzene. Catalysts such as tertiary amines or quaternary ammonium salts can be used to promote the reaction, and it is desirable to use an end-stopper, such as phenol or an alkyl-substituted phenol such as p-tert-butylphenol, as a molecular weight regulator. The reaction temperature is typically 0 to 40°C, the reaction time is several minutes to 5 hours, and the pH during the reaction is preferably maintained at 10 or higher.

[0018] The transesterification method (melt method) using a carbonate diester as a carbonate precursor involves heating and stirring a predetermined ratio of a dihydric phenol component and a carbonate diester in the presence of an inert gas, and distilling off the resulting alcohol or phenol. The reaction temperature varies depending on the boiling point of the resulting alcohol or phenol, but is typically in the range of 120 to 300°C. The reaction is carried out under reduced pressure from the beginning, allowing the resulting alcohol or phenol to be distilled off. A conventional transesterification catalyst can be used to promote the reaction. Examples of carbonate diesters used in this transesterification reaction include diphenyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate, with diphenyl carbonate being particularly preferred.

[0019] The molecular weight of the aromatic polycarbonate resin used in the present invention, expressed as a viscosity average molecular weight, is preferably 17,000 to 30,000, particularly preferably 20,000 to 26,000.Within the above range, the impact strength that is characteristic of polycarbonate resins can be maintained and excellent moldability can be achieved.

[0020] The viscosity average molecular weight of the aromatic polycarbonate resin is calculated by first determining the specific viscosity (η SP ) was measured using an Ostwald viscometer from a solution prepared by dissolving 0.7 g of polycarbonate resin material in 100 ml of methylene chloride at 20°C. Specific viscosity (η SP )=(t-t0) / t0 [t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls] The calculated specific viscosity (η SP ) and the viscosity average molecular weight Mv was calculated using the following formula: η SP / c=[η]+0.45×[η] 2 c (where [η] is the intrinsic viscosity) [η]=1.23×10 -4 Mv 0.83 c=0.7

[0021] <Benzotriazole-based weatherproofing agent (B)> The weatherproofing agent used in the present invention is a benzotriazole-based weatherproofing agent. Examples of benzotriazole-based weatherproofing agents include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-3'-dodecyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-bis(α,α'-dimethylbenzyl)phenylbenzotriazole, 2-[2'-hydroxy Examples of benzotriazole-based weather resisting agents include 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], and methyl-3-[3-tert-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenylpropionate-polyethylene glycol condensate.

[0022] Moreover, it is desirable that the benzotriazole-based weather resistance agent has a 5% weight loss temperature of 320°C or higher. Among benzotriazole-based weatherproofing agents, those having the structural formula shown in the following formula (I) can be mentioned.

[0023] [ka]

[0024] Such benzotriazole-based weathering agents have low volatility, and therefore, it is possible to obtain a resin composition that does not impair moldability or reduce transparency, and that can suppress mold contamination due to sublimation of the ultraviolet absorber during molding processing.

[0025] The amount of the benzotriazole weather resistant agent used in the present invention is 2.5 to 4.0 parts by weight, preferably 2.8 to 3.7 parts by weight, per 100 parts by weight of aromatic polycarbonate resin. If the amount of the benzotriazole weather resistant agent is less than 2.5 parts by weight, the ΔYI after 1000 hours of treatment in a sunshine weather meter becomes large, while if it exceeds 4.0 parts by weight, the Charpy impact strength becomes low.

[0026] Commercially available products of 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol] represented by the above formula (I) include "LA-31" manufactured by ADEKA Corporation, which are easily available and are preferably used.

[0027] The timing and method of blending such a benzotriazole-based weather resisting agent are not particularly limited, and it may be blended during or after polymerization of the polycarbonate resin. Furthermore, it can be mixed and melt-kneaded together with powdery, pellet- or bead-shaped polycarbonate resin in any mixer, such as a tumbler, ribbon blender, or high-speed mixer.

[0028] <Heat stabilizer (C)> The aromatic polycarbonate resin composition of the present invention may contain a heat stabilizer, such as a phosphorus-based heat stabilizer or a hindered phenol-based heat stabilizer.

[0029] The phosphorus-based heat stabilizer is preferably a phosphite-based heat stabilizer. Examples of the phosphite-based heat stabilizer include tris(nonylphenyl)phosphite, triphenylphosphite, tris(2,4-di-tert-butylphenyl)phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol-diphosphite, and 2,2'-methylenebis(4,6-di-tert-butylphenyl). Preferred are tris(phenyl)2-ethylhexyl-phosphite, tris(ethylphenyl)phosphite, tris(butylphenyl)phosphite and tris(hydroxyphenyl)phosphite, and particularly preferred are tris(nonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)2-ethylhexyl-phosphite and tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite.

[0030] The amount of the phosphorus-based heat stabilizer to be added is preferably 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.3 parts by weight, and even more preferably 0.01 to 0.2 parts by weight, relative to 100 parts by weight of the aromatic polycarbonate resin.

[0031] Examples of hindered phenolic heat stabilizers include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxyalkyl ester (alkyl has 7 to 9 carbon atoms and has a side chain), 2,4-dimethyl-6-(1-methylpentadecyl)phenol, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6 Examples of suitable hydroxybenzoates include 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0032] The amount of the hindered phenol-based heat stabilizer added is preferably in the range of 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.3 parts by weight, and even more preferably 0.01 to 0.2 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin.

[0033] The total amount of the heat stabilizer (C) added is preferably in the range of 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.4 parts by weight, and even more preferably 0.01 to 0.3 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin (A).

[0034] <Release agent (D)> The aromatic polycarbonate resin composition of the present invention may contain a mold release agent, which is preferably a saturated fatty acid ester, and examples thereof include monoglycerides such as stearic acid monoglyceride, lower fatty acid esters such as stearic acid stearate, higher fatty acid esters such as sebacate behenate, and erythritol esters such as pentaerythritol tetrastearate.

[0035] The amount of the release agent (D) added is preferably in the range of 0.05 to 0.5 parts by weight, more preferably 0.1 to 0.4 parts by weight, and even more preferably 0.12 to 0.3 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin (A).

[0036] <Bluing agent> A bluing agent can be blended into the aromatic polycarbonate resin composition of the present invention to counteract the yellow tint of the lens due to the polycarbonate resin and ultraviolet absorber. Any bluing agent that is used for polycarbonate resins can be used without any particular problems. Generally, anthraquinone dyes are easily available and are therefore preferred.

[0037] Specific examples of the bluing agent include Solvent Violet 13 (CA. No. (Color Index No.) 60725; trade names: "Macrolex Violet B" manufactured by Bayer, "Diaresin Blue G" manufactured by Mitsubishi Chemical Corporation, and "Sumiplast Violet B" manufactured by Sumitomo Chemical Co., Ltd.), Solvent Violet 31 (CA. No. 68210; trade name: "Diaresin Violet D" manufactured by Mitsubishi Chemical Corporation), Solvent Violet 33 (CA. No. 60725; trade name: "Diaresin Blue J" manufactured by Mitsubishi Chemical Corporation), Solvent Blue 94 (CA. No. 61500; trade name: "Diaresin Blue N" manufactured by Mitsubishi Chemical Corporation), Solvent Violet 36 (CA. No. 68210; trade name: "Macrolex Violet 3R" manufactured by Bayer), and Solvent Violet 38 (CA. No. 68210; trade name: "Diaresin Blue N" manufactured by Mitsubishi Chemical Corporation). Representative examples include Blue 97 (trade name "Macrolex Blue RR" manufactured by Bayer) and Solvent Blue 45 (CA. No. 61110; trade name "Tetrazole Blue RLS" manufactured by Sandoz). These bluing agents are usually blended into polycarbonate resin at a concentration of 0.3 to 5.0 ppm. If too much bluing agent is blended, the absorption of the bluing agent becomes strong, resulting in a decrease in luminous transmittance.

[0038] The blending amount of the bluing agent is preferably 0.00001 to 0.0001 part by weight, more preferably 0.000015 to 0.00005 part by weight, relative to 100 parts by weight of the aromatic polycarbonate resin. Within the above range, yellowing is effectively suppressed, and the appearance of the molded article is improved, which is preferable.

[0039] <Molded body> The aromatic polycarbonate resin composition of the present invention can be molded into a desired article according to a known molding method such as injection molding, blow molding, extrusion molding, or rotational molding. Examples of molded articles that can be suitably used in the present invention include transparent or translucent lighting covers that cover light sources such as LEDs and organic ELs that are installed outdoors, transparent covers that cover solar panels for photovoltaic power generation, and various meter covers that cover liquid crystal displays, meters, etc. [Example]

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. The raw materials used in the following examples and comparative examples are as follows:

[0041] (Aromatic polycarbonate resin (A)) Teijin Limited Panlite L-1250WP (polycarbonate resin made from bisphenol A, viscosity average molecular weight 23,900)

[0042] (Weatherproofing agent (B)) Adeka Stab LA-31 (benzotriazole-based weathering agent) manufactured by ADEKA Corporation (compound represented by formula (I)) Chemisorb 79 (benzotriazole-based UV absorber) manufactured by Chemipro Chemical Co., Ltd. BASF Tinuvin 234 (benzotriazole UV absorber) BASF Tinuvin 1577ED (triazine-based UV absorber) (comparison example) Hostavin B-CAP (malonic acid ester-based UV absorber) manufactured by Clariant Japan Co., Ltd. (Comparative example) Hostavin PR-25 (malonic acid ester-based ultraviolet absorber) manufactured by Clariant Japan Co., Ltd. (Comparative Example)

[0043] (Heat stabilizer (C)) Hostanox P-EPQ (phosphorus-based heat stabilizer; compound of formula (a) below; tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite) manufactured by Clariant Japan Co., Ltd.

[0044] [ka]

[0045] ADEKA Corporation Adeka Stab HP-10 (phosphorus-based heat stabilizer: 2,2'-Methylenebis(4,6-di-tert-butylphenyl)2-ethylhexyl phosphite) ADEKA Corporation's Adekastab PEP-36 (phosphorus-based heat stabilizer; 3,9-Bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane) BASF IRGAFOS168FF (phosphorus-based heat stabilizer: Tris(2,4-di-tert-butylphenyl)phosphite) BASF IRGANOX 1076 (hindered phenol stabilizer; Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate)

[0046] (Release agent (D)) NOF Corporation Unistar H-476-S (fatty acid ester) Rikemal S-100A (fatty acid ester) manufactured by Riken Vitamin Co., Ltd.

[0047] (Colorant (E)) Bayer "Macrolex Violet B" The evaluation methods used in the examples and comparative examples are as follows. (1) Preparation of test specimens Using a J85ELIII molding machine manufactured by Japan Steel Works, Ltd., test specimens (50 mm (width) x 90 mm (length), three-stage plates with thicknesses of 1 mm, 2 mm, and 3 mm) were prepared at a cylinder temperature of 350°C and a mold temperature of 80°C, and the following measurements were carried out.

[0048] (2) Hue evaluation The hue of the test piece (2 mm thick) molded in (1) above was measured using a spectrophotometer CE-7000A manufactured by Sakata Inx Engineering Corporation using a C2 light source and a 2-degree field of view in transmission, and the YI of the test piece was calculated. The smaller the YI value, the better. The YI value is preferably 7.0 or less.

[0049] (3) Accelerated weathering test The three-tiered plate obtained in (1) above was used as a test specimen. The test was performed using a Sunshine Weather Meter (WEL-SUN-HCH-B, manufactured by Suga Test Instruments Co., Ltd.) with a black panel temperature of 63°C, and a 120-minute cycle of 18 minutes of water spray and 102 minutes without spray, for a total of 1,000 hours. The hue of a 2-mm-thick section of the test specimen before and after treatment was measured using the method described in (2) above, and the yellowing index (ΔYI) before and after the test was calculated. A smaller ΔYI indicates less hue change and better weather resistance. ΔYI is preferably 2.5 or less, and more preferably 2.0 or less. ΔYI = YI - YI0 (ΔYI: yellowing before and after the test, YI: yellowing after the test, YI0: yellowing before the test)

[0050] (4) Haze measurement The haze of a 2 mm thick portion of the three-tiered plate of the test piece obtained in (1) above was measured in accordance with JIS K7361 using a haze meter 300A manufactured by Nippon Denshoku Industries Co., Ltd. The smaller the haze, the better the transparency. The haze is preferably 0.3% or less, and more preferably 0.2% or less.

[0051] (5) Charpy impact strength Using a J75EIII injection molding machine manufactured by The Japan Steel Works, Ltd., bending test pieces 10 mm wide, 80 mm long, and 4 mm thick were molded at a cylinder temperature of 280°C and a mold temperature of 70 to 75°C, and were measured in accordance with ISO 179. The higher the Charpy impact strength, the better. The Charpy impact strength is preferably 10 or higher, more preferably 20 or higher, and even more preferably 25 or higher.

[0052] (6) Molding retention stability (molding heat resistance) When molding the test piece in (1) above, the color (L * , a * , b *) was measured using a spectrophotometer CE-7000A manufactured by Sakata Inx Engineering Corporation using a D65 light source and a 10-degree field of view in transmission, and the color difference ΔE was calculated using the following formula (b). A smaller ΔE indicates better molding retention stability. ΔE={(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2 ...Formula (b) Color of "Formed plate before retention": L * , a * , b * Color of "formed plate after retention": L * ', a * ', b * ' ΔL * :L * -L * ' Δa * :a * -a * ' Δb * :b * -b * ' In addition, the decrease in Mv before and after the retention treatment is ΔMv (× 10 3 The smaller ΔMv is, the better the molding retention stability is. The viscosity average molecular weight (Mv) was measured by the following method.

[0053] The specific viscosity (η SP ) was measured using an Ostwald viscometer from a solution prepared by dissolving a test piece in 100 ml of methylene chloride at 20°C, and the specific viscosity (η SP ) and the viscosity average molecular weight Mv was calculated using the following formula: Specific viscosity (η SP )=(t-t0) / t0 [t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls] η SP / c=[η]+0.45×[η] 2 c (where [η] is the intrinsic viscosity) [η]=1.23×10 -4 Mv 0.83 c=0.7

[0054] (7) Dry heat resistance The test piece molded in (1) above was treated in a hot air dryer at 130°C for 1000 hours, and the hue YI (2 mm thick part) and viscosity average molecular weight of the test piece after treatment and the hue YI (2 mm thick part) and viscosity average molecular weight before treatment were measured. The difference in hue ΔYI and the difference in viscosity average molecular weight ΔMv (×10 3 ) were calculated. The smaller the ΔYI and ΔMv values, the more preferable.

[0055] (8) Moisture and heat resistance The test piece molded in (1) above was subjected to a wet heat treatment at 120°C for 24 hours in a laboratory autoclave, SN-510, manufactured by Yamato Scientific Co., Ltd., and the haze (2 mm thick part) and viscosity average molecular weight of the test piece after treatment, as well as the haze (2 mm thick part) and viscosity average molecular weight before treatment were measured. The difference in haze, ΔHaze, and the difference in viscosity average molecular weight, ΔMv (× 10 3 The smaller the ΔHaze and ΔMv values, the more preferable.

[0056] [Examples 1 to 13 and Comparative Examples 1 to 5] The raw materials were blended in the proportions shown in Table 1, then melt-kneaded at a cylinder temperature of 280°C using a vented twin-screw extruder TEX30α with a screw diameter of 30 mm manufactured by The Japan Steel Works, Ltd., and pelletized by strand cutting. The pellets were dried at 120°C for 5 hours, and then molded into test specimens for evaluation under the above conditions. The above evaluations were carried out, and the evaluation results are shown in Table 1.

[0057] [Table 1] [Industrial Applicability]

[0058] The aromatic polycarbonate resin composition of the present invention is excellent in transparency, color, weather resistance and impact resistance, and transparent molded articles obtained from the resin composition are useful as transparent molded articles for outdoor installation.

Claims

1. An aromatic polycarbonate resin composition containing 2.5 to 4.0 parts by weight of a benzotriazole-based weathering agent (B) per 100 parts by weight of an aromatic polycarbonate resin (A), The composition contains 0.001 to 0.5 parts by weight of a heat stabilizer (C) relative to 100 parts by weight of the aromatic polycarbonate resin (A), The thermal stabilizer (C) is an aromatic polycarbonate resin composition containing at least one selected from the group consisting of 2,2'-methylenebis(4,6-di-tert-butylphenyl)2-ethylhexyl-phosphite and tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite.

2. 2. The aromatic polycarbonate resin composition according to claim 1, wherein the benzotriazole-based weathering agent (B) is represented by the following formula (I): 【Chemistry 1】

3. 3. The aromatic polycarbonate resin composition according to claim 1, further comprising 0.05 to 0.5 parts by weight of a mold release agent (D) per 100 parts by weight of the aromatic polycarbonate resin (A).

4. 4. The aromatic polycarbonate resin composition according to claim 1, which has a Charpy impact strength of 10 or more.

5. 5. The aromatic polycarbonate resin composition according to claim 1, wherein the hue YI is 7.0 or less.

6. 6. The aromatic polycarbonate resin composition according to claim 1, which has a ΔYI of 2.5 or less after 1000 hours of treatment in a sunshine weather meter.

7. A molded article formed from the aromatic polycarbonate resin composition according to any one of claims 1 to 6.

8. 8. The molded article according to claim 7, which is a transparent molded article for outdoor installation.

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