THERMOPLASTIC RESIN COMPOSITION AND MOLDED ARTICLE THEREOF

Abstract

A thermoplastic resin composition contains an aromatic polycarbonate resin (A), a graft copolymer (B) prepared by graft-polymerizing one or more vinyl-based monomers (Y) onto a rubbery polymer (X), and a (meth)acrylate-based copolymer (C) prepared by polymerizing a vinyl-based monomer mixture (m1) containing a (meth)acrylate-based monomer. In the thermoplastic resin composition, preferably, 25 to 80 parts by mass of the aromatic polycarbonate resin (A), 10 to 30 parts by mass of the graft copolymer (B), and 10 to 45 parts by mass of the (meth)acrylate-based copolymer (C) are contained, based on 100 parts by mass in total of the aromatic polycarbonate resin (A), the graft copolymer (B), and the (meth)acrylate-based copolymer (C). A thermoplastic resin-molded article is obtained by molding the thermoplastic resin composition.

Claims

1. A thermoplastic resin composition, comprising an aromatic polycarbonate resin (A), a graft copolymer (B) prepared by graft-polymerizing one or more vinyl-based monomers (Y) onto a rubbery polymer (X), and a (meth)acrylate-based copolymer (C) prepared by polymerizing a vinyl-based monomer mixture (ml) containing a (meth)acrylate-based monomer.

2. The thermoplastic resin composition according to claim 1, wherein the vinyl-based monomer mixture (ml) contains an N-substituted maleimide-based monomer and/or an aromatic vinyl-based monomer.

3. The thermoplastic resin composition according to claim 1, wherein 25 to 80 parts by mass of the aromatic polycarbonate resin (A), 10 to 30 parts by mass of the graft copolymer (B), and 10 to 45 parts by mass of the (meth)acrylate-based copolymer (C) are contained, based on 100 parts by mass in total of the aromatic polycarbonate resin (A), the graft copolymer (B), and the (meth)acrylate-based copolymer (C).

4. The thermoplastic resin composition according to claim 1, wherein the (meth)acrylate-based monomer is contained in an amount of 52% to 92% by mass based on 100% by mass in total of the vinyl-based monomer mixture (m1).

5. The thermoplastic resin composition according to claim 1, wherein the rubbery polymer (X) is a silicone/acrylic-based composite rubber, and the vinyl-based monomers (Y) contain an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.

6. The thermoplastic resin composition according to claim 1, further comprising a NO-alkyl-type hindered amine-based light stabilizer (D).

7. The thermoplastic resin composition according to claim 6, wherein an alkoxy group bonded to a nitrogen atom of the NO-alkyl-type hindered amine-based light stabilizer (D) has 5 to 15 carbon atoms, and the NO-alkyl-type hindered amine-based light stabilizer (D) has a molecular weight of 500 to 1,000.

8. The thermoplastic resin composition according to claim 6, wherein the NO-alkyl-type hindered amine-based light stabilizer (D) is contained in an amount of 0.1 to 0.8 parts by mass based on 100 parts by mass in total of the aromatic polycarbonate resin (A), the graft copolymer (B), and the (meth)acrylate-based copolymer (C).

9. The thermoplastic resin composition according to claim 5, wherein the silicone/acrylic-based composite rubber is a silicone/acrylic-based composite rubber in which a polyorganosiloxane (a) and an alkyl (meth)acrylate-based polymer (b) are composited, and wherein 4% to 14% by mass of the polyorganosiloxane (a) and 96% to 86% by mass of the alkyl (meth)acrylate-based polymer (b) are contained, based on 100% by mass in total of the polyorganosiloxane (a) and the alkyl (meth)acrylate-based polymer (b).

10. The thermoplastic resin composition according to claim 1, wherein the graft copolymer (B) is prepared by graft-polymerizing 30 to 80 parts by mass of the vinyl-based monomers (Y) onto 20 to 70 parts by mass of the rubbery polymer (X) (provided that a total amount of the rubbery polymer (X) and the vinyl-based monomers (Y) is 100 parts by mass).

11. The thermoplastic resin composition according to claim 1, wherein 7% to 39% by mass of the N substituted maleimide based monomer the aromatic vinyl-based monomer and 13% or less by mass of the N-substituted maleimide-based monomer are contained, based on 100% by mass in total of the vinyl-based monomer mixture (ml).

12. A thermoplastic resin-molded article obtained by molding the thermoplastic resin composition according to claim 1.

Description

EXAMPLES

[0106] While the present invention will be described below by taking specific examples and comparative examples, the present invention is not limited to these examples below.

[0107] The symbol % refers to % by mass, and the term parts refers to parts by mass.

[Measurement and Evaluation Method]

[0108] Various measurement and evaluation methods in the following examples, comparative examples, and reference examples are described below.

<Volume-Average Particle Size of Rubbery Polymer (X)>

[0109] The volume-average particle size of the rubbery polymer (X) dispersed in an aqueous dispersion was measured with a Microtrac (Nanotrac 150, available from Nikkiso Co., Ltd.) using ion-exchanged water as a measurement solvent.

<Degree of Grafting of Graft Copolymer (B)>

[0110] First, 1 g of the graft copolymer (B) was added to 80 mL of acetone. The mixture was heated to reflux at 65 C. to 70 C. for 3 hours. The resulting suspended acetone solution was fractionated by centrifugation with a centrifuge (CR21E, available from Hitachi Koki Co. Ltd.,) at 14,000 rpm for 30 minutes into a precipitated component (acetone-insoluble component) and an acetone solution (acetone-soluble component).

[0111] The precipitated component (acetone-insoluble component) was dried. The mass (W1 (g)) thereof was measured. The degree of grafting was calculated from formula (1) below.

[0112] In formula (1), W1 is the mass (g) of the acetone-insoluble component of the graft copolymer (B), W2 is the total mass (g) of the graft copolymer (B) used in determining W1, and each rubber fraction is the solid-content concentration of an aqueous dispersion of the rubbery polymer (X) used in the production of the graft copolymer (B).

Degree of grafting (% by mass)={(W1W2rubber fraction)/W2rubber fraction}100 (1)

<Reduced Viscosity of Acetone-Soluble Component of Graft Copolymer (B)>

[0113] A solution of the graft copolymer (B) in N,N-dimethylformamide was prepared so as to have an acetone-soluble concentration of 0.2 dL/g. The reduced viscosity .sub.sp/C (unit: dL/g) of the solution was measured with an Ubbelohde viscometer at 25 C.

<Molecular Weight of (Meth)Acrylate-Based Copolymer (C) and Vinyl Copolymer (d)>

[0114] The mass-average molecular weight of the (meth)acrylate-based copolymer (C) and a vinyl copolymer (d) were determined by subjecting solutions thereof in tetrahydrofuran (THF) to gel permeation chromatography (GPC) and calculating the resulting value in terms of standard polystyrene (PS).

<Glass Transition Temperature (Tg) of (Meth)Acrylate-Based Copolymer (C)>

[0115] The glass transition temperature (Tg) of the (meth)acrylate-based copolymer (C) was determined by differential scanning calorimetry (DSC). Specifically, the glass transition temperature observed when the temperature of the (meth)acrylate-based copolymer (C) was increased from 35 C. to 250 C. at 10 C./min in a nitrogen atmosphere, decreased to 35 C., and increased again to 250 C. was determined.

[Aromatic Polycarbonate Resin (A)]

[0116] As the aromatic polycarbonate resin (A), Iupilon S-2000F (viscosity-average molecular weight (Mv): 22,000), available from Mitsubishi Engineering-Plastics Corporation, was used.

[Graft Copolymer (B)]

[0117] As the graft copolymer (B), a graft copolymer (B-1) produced by a method described below was used.

<Production of Graft Copolymer (B-1)>

[0118] The graft copolymer (B-1) that was obtained by graft-polymerizing the vinyl-based monomers (Y) onto the rubbery polymer (X) that was a composite rubber of a polyorganosiloxane rubber and an alkyl (meth)acrylate-based polymer was obtained by a method described below.

<Production of Silicone/Acrylic-Based Composite Rubber (Rubbery polymer (X))>

[0119] First, 98 parts of octamethylcyclotetrasiloxane and 2 parts of y-methacryloyloxypropyldimethoxymethylsilane were mixed to prepare 100 parts of a siloxane mixture. A solution of 0.67 parts of sodium dodecylbenzenesulfonate in 300 parts of ion-exchanged water was added thereto. The resulting mixture was stirred with a homomixer at 10,000 rpm for 2 minutes and then passed twice through a homogenizer at a pressure of 300 kg/cm.sup.2 to prepare a stable premixed organosiloxane latex.

[0120] Separately, 10 parts of dodecylbenzenesulfonic acid and 90 parts of ion-exchanged water were charged into a reactor equipped with a reagent injection container, a condenser, a jacket heater, and a stirrer to prepare a 10% aqueous solution of dodecylbenzenesulfonic acid (an aqueous solution of an acid catalyst).

[0121] The premixed organosiloxane latex was added dropwise to the aqueous solution of the acid catalyst over a period of 2 hours while the aqueous solution of the acid catalyst was heated to 85 C. After completion of the dropwise addition, the mixture was maintained at the temperature for 3 hours and then cooled to a temperature equal to or lower than 40 C. The resulting reaction product was neutralized to pH 7.0 with a 10% aqueous solution of sodium hydroxide to prepare a latex of the polyorganosiloxane (a). The latex of the polyorganosiloxane (a) was dried at 180 C. for 30 minutes, and the resulting solid content was found to be 18.2%. The average particle size on a mass basis was 30 nm.

[0122] Into a reactor equipped with a reagent injection container, a condenser, a jacket heater, and a stirrer, 200 parts of ion-exchanged water, 2 parts of potassium oleate, 4 parts of dioctyl sodium sulfosuccinate, 0.003 parts of iron(II) sulfate heptahydrate, 0.009 parts of disodium ethylenediaminetetraacetate, and 0.3 parts of sodium formaldehyde sulfoxylate were charged under a stream of nitrogen. The temperature was increased to 60 C. From the time when the temperature reached 60 C., a mixture of 85 parts of n-butyl acrylate, 15 parts of methacrylic acid, and 0.5 parts of cumene hydroperoxide was continuously added dropwise over a period of 120 minutes. After completion of the dropwise addition, aging was performed for another 2 hours while the temperature was maintained at 60 C., thereby preparing an acid group-containing copolymer latex having a solid content of 33%, a polymerization conversion of 96%, and a volume-average particle size of an acid group-containing copolymer of 120 nm.

[0123] Into a reactor equipped with a reagent injection container, a condenser, a jacket heater, and a stirrer, 5.0 parts of the latex of the polyorganosiloxane (a) in terms of solid content, 0.48 parts of dipotassium alkenylsuccinate, and 190 parts of ion-exchanged water were charged, and the mixture was mixed. A mixture, as monomers incorporated in the alkyl (meth)acrylate-based polymer (b), of 45.0 parts of n-butyl acrylate, 0.4 parts of allyl methacrylate, 0.09 parts of 1,3-butylene glycol dimethacrylate, and 0.12 parts of tert-butyl hydroperoxide was added thereto. A stream of nitrogen was passed through the reactor to replace the atmosphere with nitrogen. The internal temperature was increased to 60 C. When the internal temperature reached 60 C., an aqueous solution consisting of 0.000075 parts of iron(II) sulfate heptahydrate, 0.00023 parts of disodium ethylenediaminetetraacetate, 0.2 parts of sodium formaldehyde sulfoxylate, and 10 parts of ion-exchanged water was added thereto to initiate radical polymerization. Heat generation due to the polymerization was confirmed, and then the jacket temperature was set to 75 C. The polymerization was continued until the heat generation due to the polymerization was not observed. This state was maintained for another 1 hour, thereby preparing a composite rubber in which a polyorganosiloxane and a poly(butyl acrylate) rubber were composited (radical polymerization step). The resulting composite rubber had a volume-average particle size of 90 nm.

[0124] The temperature of the liquid in the reactor was decreased to 70 C., and then a 5% aqueous solution of sodium pyrophosphate was added in an amount of 0.20 parts in terms of solid content. The internal temperature was controlled at 70 C., and then the acid group-containing copolymer latex was added thereto in an amount of 0.30 parts in terms of solid content. The mixture was stirred for 30 minutes for enlargement, thereby preparing a latex of the rubbery polymer (X) (enlargement step).

[0125] The resulting rubbery polymer (X) in latex form had a volume-average particle size of 159 nm. The percentage of particles having a particle size of 300 to 500 nm in all particles of the rubbery polymer (X) was 10% by volume.

<Production of Graft Copolymer (B-1)>

[0126] An aqueous solution consisting of 0.001 parts of iron(II) sulfate heptahydrate, 0.003 parts of disodium ethylenediaminetetraacetate, 0.3 parts of Rongalite, and 10 parts of ion-exchanged water was added to the latex of the rubbery polymer (X). A liquid mixture of 10 parts of acrylonitrile, 30 parts of styrene, and 0.18 parts of tert-butyl hydroperoxide was added dropwise thereto over a period of 80 minutes, and polymerization was performed. After completion of the dropwise addition, the temperature was maintained at 75 C. for 30 minutes. A mixture of 2.5 parts of acrylonitrile, 7.5 parts of styrene, 0.05 parts of tert-butyl hydroperoxide, and 0.02 parts of n-octyl mercaptan was added dropwise thereto over a period of 20 minutes, and polymerization was performed. After completion of dropwise addition, the temperature was maintained at 75 C. for 30 minutes. Cumene hydroperoxide was added thereto in an amount of 0.05 parts. The temperature was maintained at 75 C. for another 30 minutes. The mixture was then cooled to provide a latex of silicone/acrylic composite rubber-based graft copolymer (B-1) obtained by graft-polymerizing acrylonitrile and styrene onto the rubbery polymer (X). Next, 150 parts of a 1% aqueous solution of calcium acetate was heated to 60 C., and then 100 parts of the latex of the graft copolymer was slowly added dropwise thereto to obtain a precipitate. The precipitate was separated, dehydrated, washed, and dried to give the graft copolymer (B-1).

[0127] The acetone-soluble component of the graft copolymer (B-1) was contained in an amount of 26%, and the degree of grafting was 45%. The acetone-soluble component had a reduced viscosity of 0.60 dL/g.

[(Meth)Acrylate-Based Copolymer (C)]

[0128] As the (meth)acrylate-based copolymer (C), (meth)acrylate-based copolymers (C-1), (C-3), and (C-4) produced by methods described below and commercial products (C-2) and (C-5) described below were used.

<Production of (Meth)Acrylate-Based Copolymer (C-1)>

[0129] First, 0.1 parts of Perbutyl PV (available from NOF Corporation), 0.05 parts of Perbutyl O (available from NOF Corporation), 0.05 parts of Perhexa HC (available from NOF Corporation), 0.6 parts of tert-dodecyl mercaptan, and 0.2 parts of -methylstyrene dimer were mixed with 100 parts of a vinyl-based monomer mixture of 76 parts of methyl methacrylate (MMA), 8 parts of N-phenylmaleimide (N-PMI), and 16 parts of styrene (ST) in advance. To the resulting mixture, 200 parts of deionized water containing 0.5 parts of tribasic calcium phosphate and 0.003 parts of potassium alkenylsuccinate was added. The mixture was charged into a 20-L pressure-tight reaction tank equipped with a stirrer. Polymerization was initiated from 40 C. The reaction was performed for 9 hours at a rate of temperature increase of 5 to 10 C./h during the polymerization reaction. After completion of the polymerization at 120 C., the mixture was subjected to cooling, washing, filtration, and drying steps to provide the (meth)acrylate-based copolymer (C-1) in a polymeric bead-like form.

[0130] The mass composition ratio, the mass-average molecular weight (Mw), and the glass transition temperature (Tg) of the (meth)acrylate-based copolymer (C-1) were measured and found to be the following. [0131] Mass composition ratio: MMA/N-PMI/ST=76/8/16 [0132] Mass-average molecular weight (Mw): 90,500 [0133] Glass transition temperature (Tg): 120 C.

<(Meth)Acrylate-Based Copolymer (C-2)>

[0134] Acrypet VH5, available from Mitsubishi Chemical Corporation, having a methyl methacrylate (MMA)/methyl acrylate (MA) ratio described below was used. [0135] Mass composition ratio: MMA/MA=98/2 [0136] Mass-average molecular weight (Mw): 72,000 [0137] Glass transition temperature (Tg): 114 C.

<Production of (Meth)Acrylate-Based Copolymer (C-3)>

[0138] A copolymer was synthesized by a suspension polymerization method as described below.

[0139] In a nitrogen-purged reactor, 120 parts of water, 0.002 parts of a sodium alkylbenzenesulfonate, 0.5 parts of poly(vinyl alcohol), 0.3 parts of azoisobutyronitrile, 0.5 parts of tert-DM, and a monomer mixture of 24 parts of acrylonitrile (AN), 30 parts of styrene (ST), and 46 parts of methyl methacrylate (MMA) were used. The temperature was increased from a starting temperature of 60 C. for 5 hours while portions of styrene were sequentially added to the resulting mixture, and reached 120 C. The reaction was performed at 120 C. for another 4 hours. The resulting polymeric substance was taken out to obtain the (meth)acrylate-based copolymer (C-3).

[0140] The mass composition ratio and the mass-average molecular weight (Mw) of the resulting (meth)acrylate-based copolymer (C-3) were measured and found to be the following. [0141] Mass composition ratio: AN/ST/MMA=24/30/46 [0142] Mass-average molecular weight (Mw): 98,000 [0143] Glass transition temperature (Tg): 98 C.

<Production of (Meth)Acrylate-Based Copolymer (C-4)>

[0144] A copolymer was synthesized by a suspension polymerization method as described below.

[0145] In a nitrogen-purged reactor, a monomer mixture of 120 parts of water, 0.002 parts of a sodium alkylbenzenesulfonate, 0.5 parts of poly(vinyl alcohol), 0.3 parts of azoisobutyronitrile, 0.5 parts of tert-dodecyl mercaptan, 11 parts of acrylonitrile (AN), 5 parts of styrene (ST), 69 parts of methyl methacrylate (MMA), and 15 parts of -methylstyrene (a-MST) was used. The temperature was increased from a starting temperature of 60 C. for 5 hours while portions of styrene were sequentially added to the resulting mixture, and reached 120 C. The reaction was performed at 120 C. for another 4 hours. The resulting polymeric substance was taken out to obtain the (meth)acrylate-based copolymer (C-4).

[0146] The mass composition ratio and the mass-average molecular weight (Mw) of the resulting (meth)acrylate-based copolymer (C-4) were measured and found to be the following. [0147] Mass composition ratio: AN/ST/MMA/-MST=11/5/69/15 [0148] Mass-average molecular weight (Mw): 100,000 [0149] Glass transition temperature (Tg): 113 C.

<Meth)Acrylate-Based Copolymer (C-5)>

[0150] Polyimilex PML203, available from Nippon Shokubai Co., Ltd., having a methyl methacrylate (MMA)/N-phenylmaleimide (N-PMI)/cyclohexylmaleimide (CHMI)/styrene (ST) ratio described below was used. [0151] Mass composition ratio: MMA/N-PMI/CHMI/ST=82/6/6/6 [0152] Mass-average molecular weight (Mw): 121,000 [0153] Glass transition temperature (Tg): 104 C.
[Vinyl Copolymer (e)]

[0154] A vinyl copolymer (e) used in comparative examples below was produced by a suspension polymerization method as described below.

<Production of Vinyl Copolymer (e-1)>

[0155] In a nitrogen-purged reactor, 120 parts of water, 0.002 parts of a sodium alkylbenzenesulfonate, 0.5 parts of poly(vinyl alcohol), 0.3 parts of azoisobutyronitrile, 0.5 parts of tert-dodecyl mercaptan, and a monomer mixture of 26 parts of acrylonitrile (AN) and 74 parts of styrene (ST) were used. The temperature was increased from a starting temperature of 60 C. for 5 hours while portions of styrene were sequentially added to the resulting mixture, and reached 120 C. The reaction was performed at 120 C. for another 4 hours. The resulting polymeric substance was taken out to obtain the vinyl copolymer (e-1) having an AN/ST ratio of 26/74 (mass ratio) and a mass-average molecular weight (Mw) of 110,000.

[NO-Alkyl-Type Hindered Amine-Based Light Stabilizer (D)]

<NO-Alkyl-Type Hindered Amine-Based Light Stabilizer (D-1)>

[0156] STAB LA-81, available from Adeka Corporation, molecular weight: 681

<NO-Alkyl-Type Hindered Amine-Based Light Stabilizer (D-2)>

[0157] Tinuvin PA123, available from BASF, molecular weight: 737

[Other Hindered Amine-Based Light Stabilizer (d)]
<NCH.sub.3-Type Hindered Amine-Based Light Stabilizer (d-1)>

[0158] ADK STAB LA-52, available from Adeka Corporation, molecular weight: 847

<NH-Type Hindered Amine-Based Light Stabilizer (d-2)>

[0159] ADK STAB LA-57, available from Adeka Corporation, molecular weight: 791

[0160] The structures of other hindered amine-based light stabilizers (d) are described below.

##STR00002##

[Injection Molding Method]

[0161] Molded articles used for evaluation were formed as described below.

<Injection Molding 1>

[0162] Pellets composed of a thermoplastic resin composition were molded with an injection molding machine (IS55FP-1.5A, available from Toshiba Machine Co., Ltd.) at a cylinder temperature of 200 C. to 270 C. and a mold temperature of 60 C. into molded articles each having a length of 63.5 mm, a width of 12.7 mm, and a thickness of 6.2 mm. The molded articles were used as molded articles (notched) for an Izod impact test, molded articles for measuring flexural moduli, and molded articles for measuring deflection temperatures under load.

<Injection Molding 2>

[0163] Pellets composed of a thermoplastic resin composition were molded with an injection molding machine (IS55FP-1.5A, available from Toshiba Machine Co., Ltd.) at a cylinder temperature of 200 C. to 270 C. and a mold temperature of 60 C. into molded articles each having a length of 100 mm, a width of 100 mm, and a thickness of 3 mm. The molded articles were used as molded articles for evaluation of color developability and molded articles for evaluation of weather resistance.

[Evaluation Method]

[0164] Evaluation methods are described below.

<Evaluation of Impact Resistance: Izod Impact Test>

[0165] The molded articles produced in Injection molding 1 were subjected to an Izod impact test (notched) according to the standard ASTM D 256 at 23 C. or both at 23 C. and -30 C. to measure the Izod impact strength. A higher Izod impact value indicates better impact resistance.

<Evaluation of Stiffness: Flexural Test>

[0166] The flexural modulus of each of the molded articles produced in Injection molding 1 was measured according to the standard ASTM D 790. A higher flexural modulus indicates better stiffness.

<Evaluation of Heat Resistance: Measurement of Deflection Temperature Under Load>

[0167] The deflection temperature under load (HDT) ( C.) of each of the molded article produced in Injection molding 1 was measured according to the standard ASTM D 648 by an edgewise method and evaluated according to the following evaluation criteria.

(Evaluation Criteria)

[0168] HDT is 105 C. or higher: O excellent for practical use [0169] HDT is lower than 105 C. and 103 C. or higher: adequate for practical use [0170] HDT is lower than 103 C.: X poor for practical use

<Evaluation of Color Developability: Measurement of Lightness L*>

[0171] The lightness L* of the molded articles produced in Injection molding 2 were measured with a spectrocolorimeter (CM-3500d, available from Konica Minolta Optics, Inc.) in an SCE mode. A lower L* value indicates a blacker color, which is excellent in color developability.

<Evaluation of Durability: High-Temperature and High-Humidity Test>

[0172] The molded articles produced in Injection molding 1 were exposed to a high-temperature and high-humidity environment with a temperature of 85 C. and a humidity of 85% for 200 hours. Then the Izod impact test (notched) was performed in the same manner as above to measure the Izod impact strength. The retention (%) of the Izod impact strength before and after exposure to the constant-temperature and high-humidity environment was calculated. Evaluation criteria are described below.

(Evaluation Criteria)

[0173] The retention of the Izod impact strength is 50% or more: excellent in durability

[0174] The retention of the Izod impact strength is 40% and less than 50%: adequate durability for practical use

[0175] The retention of the Izod impact strength is less than 40%: poor in durability

<Evaluation of Weather Resistance: Measurement of E* Before and After Accelerated Test>

[0176] An accelerated test was performed for 200 hours with EYE Super UV Tester (Model: SUV-W151, available from Iwasaki Electric Co., Ltd.) under the following conditions: black panel temperature: 63 C., and cycle: 360 minutes (irradiation at an illuminance of 100 mW/cm.sup.2 for 240 minutes (humidity: 50%).fwdarw.shower: 10 seconds.fwdarw.blackness: 120 minutes (humidity: 95%). The color difference E* before and after the accelerated test was measured with a spectrocolorimeter (CM-3500d, available from Konica Minolta Optics, Inc.) in an SCE mode. A smaller E* indicates better weather resistance.

[Examples I-1 to 11 and Comparative Example I-1 and 2]

[0177] Components were mixed according to formulations (parts by mass) presented in Table 1. Furthermore, 0.8 parts of carbon black was mixed thereto. The resulting mixtures were melt-kneaded at 240 C. with a twin-screw extruder having a vacuum vent having a diameter of 32 mm (TEX-30, available from Japan Steel Works, Ltd.) to produce pellets of the thermoplastic resin compositions. Molded articles produced by subjecting the pellets of the thermoplastic resin compositions to injection molding were evaluated by the above methods. Table 1 presents the results.

TABLE-US-00001 TABLE 1 Example I-1 I-2 I-3 I-4 I-5 I-6 I-7 Formulation Aromatic polycarbonate resin (A) parts by 50 40 80 40 40 60 60 mass Graft copolymer (B) B-1 parts by 20 20 10 30 15 10 30 mass (Meth)acrylate-based copolymer (C) C-1 parts by 30 40 10 30 45 30 10 mass C-2 parts by mass C-3 parts by mass C-4 parts by mass C-5 parts by mass Vinyl copolymer (e) e-1 parts by mass Evaluation Impact Izod Normal ASTM J/m 600 550 700 600 400 550 700 result resistance impact temperature D 256 value (23 C.) Low 55 50 120 55 40 50 100 temperature (30 C.) Stiffness Flexural modulus ASTM MPa 2450 2500 2400 2400 2400 2400 2300 D 790 Heat Deflection ASTM C. resistance temperature D 648 under load Color L* SCE L* 6 6 7 6 5 6 7 developability mode Comparative Example example I-8 I-9 I-10 I-11 I-1 I-2 Formulation Aromatic polycarbonate resin (A) parts by 50 50 50 50 80 50 mass Graft copolymer (B) B-1 parts by 20 20 20 20 20 20 mass (Meth)acrylate-based copolymer (C) C-1 parts by mass C-2 parts by 30 mass C-3 parts by 30 mass C-4 parts by 30 mass C-5 parts by 30 mass Vinyl copolymer (e) e-1 parts by 30 mass Evaluation Impact Izod Normal ASTM J/m 430 465 420 460 700 650 result resistance impact temperature D 256 value (23 C.) Low 35 25 30 30 120 60 temperature (30 C.) Stiffness Flexural modulus ASTM MPa 2350 2350 2300 2300 2100 2150 D 790 Heat Deflection ASTM C. x resistance temperature D 648 under load Color L* SCE L* 6 8 7 6 9 9 developability mode

[0178] As presented in Examples I-1 to 11, the molded articles obtained from the thermoplastic resin compositions each containing the aromatic polycarbonate resin (A), the graft copolymer (B), and the (meth)acrylate-based copolymer (C) according to the present invention are excellent in all of the color developability, impact resistance, stiffness, and heat resistance.

[0179] In contrast, Comparative example I-1 reveals the results of a typical PC/ABS resin containing no (meth)acrylate-based copolymer (C). Although the impact resistance and the heat resistance are satisfactory, the color developability is poor.

[0180] Comparative example 1-2 reveals the results when the copolymer different from the (meth)acrylate-based copolymer (C) was used. Although the impact resistance is satisfactory, the stiffness, the heat resistance, and the color developability are poor.

[Examples II-1 to 14, Comparative Examples II-1 and 2, and Reference Example II-1]

[0181] Components were mixed according to formulations (parts by mass) presented in Tables 2A and 2B. Furthermore, 0.8 parts of carbon black was mixed thereto. The resulting mixtures were melt-kneaded at 240 C. with a twin-screw extruder having a vacuum vent having a diameter of 32 mm (TEX-30, available from Japan Steel Works, Ltd.) to produce pellets of the thermoplastic resin compositions. Molded articles produced by subjecting the pellets of the thermoplastic resin compositions to injection molding were evaluated by the above methods. Tables 2A and 2B present the results. Reference example II-1 corresponds to Example I-1 described above.

TABLE-US-00002 TABLE 2A Example II-1 II-2 II-3 II-4 II-5 II-6 II-7 II-8 II-9 Formulation Aromatic polycarbonate parts by 50 50 50 40 80 40 40 60 60 resin (A) mass Graft copolymer (B) B-1 parts by 20 20 20 20 10 30 15 10 30 mass (Meth)acrylate-based C-1 parts by 30 30 30 40 10 30 45 30 10 copolymer (C) mass C-2 parts by mass C-3 parts by mass C-4 parts by mass C-5 parts by mass NO-alkyl-type hindered D-1 parts by 0.5 0.1 0.8 0.5 0.5 0.5 0.5 0.5 0.5 amine-based light mass stabilizer (D) D-2 parts by mass Other NCH.sub.3 d-1 parts by hindered type mass amine- NH d-2 parts by based light type mass stabilizer (d) Impact Izod ASTM J/m 640 580 710 650 850 750 470 700 850 resistance impact D 256 strength (23 C.) Durability Retention % 60 55 50 60 50 62 65 50 50 of Izod impact strength (after 200 hours) Color L* SCE L* 4 4.5 3.8 5 5 5 4 4 5 developability mode Weather E* SCE E* 14 15 13 11 17 11 11 15 16 resistance mode

TABLE-US-00003 TABLE 2B Reference Comparative Example example example II-10 II-11 II-12 II-13 II-14 II-1 II-1 II-2 Formulation Aromatic polycarbonate resin (A) parts by 50 50 50 50 50 50 50 50 mass Graft copolymer (B) B-1 parts by 20 20 20 20 20 20 20 20 mass (Meth)acrylate-based C-1 parts by 30 30 30 30 copolymer (C) mass C-2 parts by 30 mass C-3 parts by 30 mass C-4 parts by 30 mass C-5 parts by 30 mass NO-alkyl-type hindered D-1 parts by 0.5 0.5 0.5 0.5 amine-based light mass stabilizer (D) D-2 parts by 0.5 mass Other NCH.sub.3 d-1 parts by 0.5 hindered type mass amine- NH d-2 parts by 0.5 based type mass light stabilizer (d) Impact Izod impact ASTM J/m 550 520 500 600 620 600 300 350 resistance strength D 256 (23 C.) Durability Retention % 55 53 55 60 61 45 10 55 of Izod impact strength (after 200 hours) Color L* SCE L* 5 5 5 5 4 6 5 5 developability mode Weather E* SCE E* 15 16 15 15 14 20 19 20 resistance mode

[0182] As presented in Examples II-1 to 14, the molded articles obtained from the thermoplastic resin compositions each containing the aromatic polycarbonate resin (A), the graft copolymer (B), the (meth)acrylate-based copolymer (C), and the NO-alkyl-type hindered amine-based light stabilizer (D) according to the present invention are excellent in impact resistance, color developability, durability, and weather resistance, and are suitable for the design of a wide variety of products.

[0183] In Reference example II-1, the NO-alkyl-type hindered amine-based light stabilizer (D) is not added; thus, the impact resistance durability, the color developability, and the weather resistance are poor.

[0184] In Comparative examples II-1 and 2, the NCH.sub.3-type or NH-type hindered amine-based light stabilizer different from the NO-alkyl-type hindered amine-based light stabilizer (D) was used. The impact resistance, in particular, the durability is significantly poor.

[0185] While the present invention has been described in detail using a specific embodiment, it should be apparent to those skilled in the art that various modifications can be made without departing from the spirit and the scope of the present invention.

[0186] This application is based on Japanese Patent Application No. 2018-049691 filed Mar. 16, 2018, which is hereby incorporated by reference herein in its entirety.

INDUSTRIAL APPLICABILITY

[0187] The thermoplastic resin composition containing the aromatic polycarbonate resin (A), the graft copolymer (B), and the (meth)acrylate-based copolymer (C) according to the present invention is excellent in impact resistance, stiffness, heat resistance, and color developability (coloration properties) and thus enables the resulting molded article to have excellent appearance.

[0188] The thermoplastic resin composition containing the aromatic polycarbonate resin (A), the graft copolymer (B), the (meth)acrylate-based copolymer (C) and the NO-alkyl-type hindered amine-based light stabilizer (D) according to the present invention is excellent in impact resistance, color developability, durability, and weather resistance and thus enables the resulting molded article to have excellent appearance.

[0189] The molded article obtained by molding the thermoplastic resin composition of the present invention can be widely used in various fields, such as office automation apparatus fields, electronic and electrical apparatus fields, and automotive fields. For example, the molded article can be used in a wide variety of applications in accordance with the needs of the market and has very high industrial utility.