Thermoplastic resin composition and molded article

Abstract: A thermoplastic resin composition comprising an aromatic polycarbonate resin and an aromatic polysulfone resin and having the specific melt viscosity ratio between the two resins in the composition. This composition is excellent in heat resistance and gives a molded article of especially high temperature of deflection under load.

Description: The present invention relates to a thermoplastic resin composition which is excellent in mechanical properties, heat resistance and moldability, and a molded article thereof. For the purpose of improving the chemical resistance of an aromatic polycarbonate resin, and improving the impact resistance and the flowability during mold processing of an aromatic polysulfone resin, various thermoplastic resin compositions comprising an aromatic polycarbonate resin and an aromatic polysulfone resin are disclosed. For example, JP-B-45-39181 discloses that chemical resistance and thermal stress brittleness are improved compared with each resin by mixing an aromatic polysulfone resin and an aromatic polycarbonate resin. JP-B-49-13855 discloses that a composition comprising an aromatic polysulfone resin and an aromatic polycarbonate resin is excellent in heat-deformation resistance compared with ABS resin. JP-A-54-28361 discloses that a composition comprising an aromatic polycarbonate resin having a weight average molecular weight of larger than 60000 and an aromatic polysulfone resin, has improved chemical resistance and good temperature of deflection under load compared with the respective resins. Moreover, JP-A-60-51739 discloses that a composition comprising an aromatic polysulfone resin and an aromatic polycarbonate resin containing specific structures is excellent in mechanical properties, and improved in chemical resistance. However, the above described compositions can not satisfy the physical properties in many cases, since an aromatic polycarbonate resin lowers the excellent physical properties, such as the heat resistance which is inherent in an aromatic polysulfone resin. JP-A-60-5108 discloses a microwave oven container comprising an aromatic polysulfone resin. However, a container comprising an aromatic polysulfone resin alone has sometimes insufficient flowability during mold processing, and it is hard to obtain a molded article having a good appearance. For a lamp reflector (referred to as "a reflecting mirror", sometimes), especially for a head lamp reflector and a fog lamp reflector of cars, a metallic material such as a sheet steel or a glass material has been conventionally used. In recent years, various designs are demanded and a resin material having excellent processing properties and a high degree of freedom has been demanded. Under such a background, a bulk molding compound (BMC) in which an unsaturated polyester resin is reinforced with inorganic fillers, such as glass fibers, came to be used as a material for the above use. Further, as a lamp reflector material, a polycarbonate and a polyphenylene sulfide resin which are thermoplastic engineering plastics, have been examined for the purpose of improving recycle properties of the materials, performance, and mold processing properties. However, in the use of a halogen lamp with a high temperature of light source, or in the use of a projector type reflector from which a large quantity of light can be obtained, there may be a problem that the heat resistance is insufficient resulting in heat deformations. in order to raise the forward visibility of a vehicle, reflection properties on the surface of a reflector is important, and the surface needs to be smooth. Therefore, an undercoat processing is made on the surface of a molded material and it is industrially disadvantageous. A purpose of the present invention is to provide a thermoplastic resin composition which is excellent in heat resistance and which gives a molded article exhibiting an especially high temperature of deflection under load. Another purpose of the present invention is to provide microwave oven parts having high heat resistance, high mechanical strength, and outstanding appearance, and to provide a reflector for lamps. According to the present invention, there is provided a composition comprising an aromatic polycarbonate resin and an aromatic polysulfone resin and having a specific melt viscosity ratio between the two resins in the composition. That is, the present invention is as follows. [1] A thermoplastic resin composition comprising 25 to 45% by weight of an aromatic polycarbonate resin, and 75 to 55% by weight of an aromatic polysulfone resin consisting of the repeating unit represented by the following formula wherein the ratio (ηa/ηb) of the melt viscosity (ηa) of the aromatic polycarbonate resin to the melt viscosity (ηb) of the aromatic polysulfone resin defined below is 0.5 to 2.0, wherein ηa is the melt viscosity of the aromatic polycarbonate resin measured at a temperature of 340°C and a shear rate of 1216/second through an orifice having a diameter of 1 mm and a length of 10 mm, ηb is the melt viscosity of the aromatic polysulfone resin measured at a temperature of 340°C and a shear rate of 1216/second through an orifice having a diameter of 1 mm and a length of 10 mm, and ηa is in the range of from 2,000 to 10,000 poises, and ηb is in the range of from 1,000 to 6,000. [2] The thermoplastic resin composition comprising 100 parts by weight of the thermoplastic resin composition of claim 1, and 1 to 10 parts by weight of titanium oxide having a number average particle diameter of 0.01 to 5 µm. [3] The thermoplastic resin composition comprising 100 parts by weight of the thermoplastic resin compositions of claim 1, and 1 to 80 parts by weight of a filler selected from the group consisting of clay, kaolin and talc. [4] The thermoplastic resin composition according to claim 1, 2 or 3, wherein the ratio (ηa/ηb) is 0.8 to 1.8. [5] The thermoplastic resin composition according to claim 1, 2 or 3, wherein the aromatic polycarbonate resin is a co-polycarbonate or a homo-polycarbonate containing at least 30 mol% of bisphenol A unit. [6] A molded article obtainable from the thermoplastic resin composition of claim 1, 2 or 3. [7] Microwave oven parts molded by using the thermoplastic resin composition of claim 1 or 2, wherein said parts are an axial receptacle, a rotational gear, a saucer or a container for food cooking for use in a microwave oven. [8] The microwave oven parts according to claim 7, wherein the parts are a saucer or a container for food cooking for use in a microwave oven. [9] A lamp reflector comprising the thermoplastic resin composition of claim 1 or 3: [10] The lamp reflector according to claim 9, wherein the lamp reflector is a head lamp for cars, a reflector for fog lamps or a sub-reflector for head lamps. The aromatic polycarbonate resins used in the present invention are homopolymers, copolymers and mixtures thereof containing a repeating unit represented by the general formula below. In the formula, A is a divalent aromatic group which is a residue of a dihydric phenol. Dihydric phenols which can be used in order to produce such an aromatic polycarbonate is a single- or plural-nucleus aromatic compound containing two hydroxyl groups as functional groups which bond directly to aromatic carbon atoms. Examples of the dihydric phenol include 2,2-bis(4-hydroxy phenyl)propane(bisphenol A), bis(4-hydroxy phenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-(3,5,3',5'-tetrachloro-4,4'-hydroxy phenyl)propane, 2,2-(3,5,3',5'-tetrabromo-4,4'-hydroxy phenyl)propane, 1,1-bis(4-hydroxy phenyl)cyclohexane, hydroquinone, resorcinol and dihydroxy diphenyl, without being limited thereto. The aromatic polycarbonate resin is preferably a co-polycarbonate having more than 30 mol% of bisphenol A unit or a homo-polycarbonate. The terminal structure is determined according to the preparation process, and for example, OH and OC(CH3)3 are included, without being limited thereto. As for the melt viscosity of the aromatic polycarbonate resin used in the present invention, measured at 340 °C and a shear rate of 1216/second, it is 2000 - 10000 poise, and preferably 2000 - 6000 poise. When the melt viscosity exceeds 10000 poise, the melt viscosity of the composition becomes high to make the mold processing difficult, which is not preferable. The aromatic polysulfone resin used in the present invention consists of the repeating unit represented by the following formula Polysulfones, outside the present invention, can include the following repeating units The compound (II) comprises a random copolymer. In the formula, R 1 represents an alkyl group having 1-6 carbon atoms, an alkenyl group having 3-10 carbon atoms, a phenyl group, or a halogen atom; p is an integer of 0 to 4; m and n represent average number of repeating units, and m and n are within the range of 0.1 to 100; each R 1 on the same or different nucleus may differ mutually; p may differ each mutually. This compound comprises a random copolymer. In the formula, R 1 represents an alkyl group having 1-6 carbon atoms, an alkenyl group having 3-10 carbon atoms, a phenyl group, or a halogen atom; p is an integer of 0 to 4; q, m and n represent average number of repeating units, q is a numeral of 1 to 3, m and n are within the range of 0.1 to 100; each R 1 on the same or different nucleus may differ mutually; p may differ each mutually. As for the aromatic polysulfone resin, the value of (m/m+n) in the repeating unit represented by (II) or (III) is preferably not less than 0.8. Moreover, q in the structural unit of (III) is preferably 1. Among them, a polysulfone having the repeating units of (I) and (II) is preferable, and a polysulfone having the repeating unit of (I) is more preferable. As examples of a commercial product, SUMIKAEXCEL PES 3600P and 4100P (tradename; manufactured by Sumitomo Chemical Co. ,Ltd.) are exemplified as polysulfones according to the present invention and UDEL P-1700 (tradename; manufactured by AMOCO company) is exemplified as for (II), without being limited thereto. The terminal structure is determined according to the preparation process of each resin, and Cl, OH, OR (R is an alkyl group), etc. are exemplified without being limited thereto. As for the melt viscosity of the aromatic polysulfone resin used in the present invention measured at 340 °C and a shear rate of 1216/second, it is 1000 - 6000 poise, and preferably 1000 - 3000 poise. When the melt viscosity exceeds 6000 poise, the melt viscosity of a composition is high and the mold processing becomes difficult, which is not preferable. The ratio (ηa/ηb) of the melt viscosity of aromatic polycarbonate resin (a) to aromatic polysulfone resin (b) used in the present invention measured at 340 °C and a shear rate of 1216/second are 0.5-2.0. It is preferably 0.8-1.8, and more preferably 1.0-1.6. When η a/η b is smaller than 0.5, the heat resistance of the composition is inferior and it is not preferable. The amount of aromatic polycarbonate resin contained in a resin composition of the present invention is 25-45 % by weight on the basis of the total weight of aromatic polysulfone resin and aromatic polycarbonate resin. If the amount of aromatic polycarbonate resin is more than 55 % by weight, the heat resistance of the composition is inferior, which is not preferable. Titanium oxide used in the present invention will not be limited as long as the main component of it is an oxide of titanium, but the compound containing titanium dioxide as a main component is preferable. The crystal form of the titanium oxide is not especially limited, namely, a rutile type, an anatase type and a brookite type are exemplified. Among them, especially a rutile type is preferable. Although the preparation process of titanium oxide is not especially limited, there can be exemplified the sulfuric acid method in which ilmenite as a raw material is treated with sulfuric acid, and the chlorine method in which rutile as a raw material is treated by chlorine gas. Titanium oxide whose surface is treated with one or more metallic compounds selected from aluminium, silicon, zirconia, zinc and manganese, has a good affinity with the aromatic polysulfone resin and the aromatic polycarbonate resin used in the present invention. Since it gives an excellent appearance to a molded article, it is especially preferable. The method of the surface treatment of titanium oxide is not especially limited. On the surface of titanium oxide, compounds can be deposited after steps such as neutralization and drying, from e.g. an aqueous solution of the hydroxide of each metal or a composite oxide like sodium aluminate, composite hydroxide, or its hydrate. The form of the titanium oxide particles is not especially limited in the present invention. Spherical titanium oxide having a number average particle diameter of 0.01-5 µm is preferable. Spherical titanium oxide having a number average particle diameter of 0.02-1 µm is more preferable. If the particle diameter of titanium oxide is larger than 5 µm, a screw of a granulating machine and a die of a molding machine are abraded by the hardness of titanium oxide, and it is not preferable. If the particle diameter of the surface-treated titanium oxide is smaller than 0.01 µm, a strand becomes easy to be cut during granulation, and stable granulation becomes impossible, which is not preferable. The number average particle diameter here is calculated on the basis of the accumulation particle size distribution measured by laser scattering method. As an example of a measurement device, MASTERSIZER (manufactured by Malvern Instruments Ltd) is mentioned. In the present invention, the amount of titanium oxide added to 100 parts by weight of a thermoplastic resin composition is 0.5 to 20 parts by weight, and preferably, it is 1 to 10 parts by weight. If the amount of titanium oxide is more than 20 parts by weight, the biting property into screw becomes bad, the plasticization during mold processing becomes unstable, and it is not preferable. The thermoplastic resin composition of the present invention is used for microwave oven parts. Microwave oven parts mean parts, such as a saucer and a container for cooking on the saucer used in a microwave oven, an axial receptacle, and a rotation gear. The resin composition used in the present invention is suitable especially for a saucer or a container for food cooking used in a microwave oven. Clay used in the present invention is pyrophyllite as fine powder. Generally, pyrophyllite clay is used. Pyrophyllite clay has a composition represented by Al 2 Si 4 O 10 (OH) 2 , and has an irregular hexagonal, or leaflet shape. In the present invention, from the viewpoint of processability and a surface property, clay having a weight average particle diameter of 20 µm or less is preferable. Kaolin used for the present invention is a powder having a composition represented by Al 2 Si 2 O 5 (OH) 4 . There are three types of kaolins, namely, kaolinite, dickite, and nacrite, and either of them can be used. In the present invention, from the viewpoint of processability and a surface property, kaolin having a weight average particle diameter of 20 µm or less is preferable. Talc used for the present invention is a white fine powder of a composition represented by Mg 3 (Si 4 O 10 )(OH) 2 having a layer structure, and generally it is used as a lubricant. In the present invention, from the viewpoint of processability or surface properties, talc having a weight average particle diameter of 20 µm or less is preferable. In the present invention, when clay, kaolin or talc is added, the amount of clay, kaolin or talc to 100 parts by weight of thermoplastic resin compositions is 0.5-200 parts by weight, preferably 1-80 parts by weight. If the amount of clay, kaolin or talc is more than 200 parts by weight, feeding property to the screw becomes bad during granulation and the mechanical strength falls remarkably which is not preferable. The thermoplastic resin composition of the present invention may be used for a lamp reflector. Especially, a thermoplastic resin composition containing clay, kaolin or talc has high heat resistance, mechanical strength, and surface smoothness, and it is preferable. As a lamp reflector, a head lamp for cars, a reflector for fog lamps, or a sub-reflector for head lamps is mentioned. A lamp reflector of the present invention can be produced by a well-known method, and following preparation steps are exemplified. (1) A lamp reflector of a needed design is molded by injection molding. To improve surface smoothness, an undercoat material is coated and cured. In the present invention, since the surface smoothness of a molded article is high, this process may be omissible. (2) Aluminum is deposited on the molded article surface. The thickness of deposited aluminum is usually several µm. (3) Top coating is applied. In the present invention, if necessary, one or more of usual additives described below can be added. Fibrous or needlelike reinforcements such as glass fibers silica alumina fibers, alumina fibers, carbon fibers or aluminum borate whiskers; inorganic fillers, such as talc, mica, clay or glass beads; mold release agents, such as a fluoropolymer or metal soaps; colorants, such as dyes or pigments, antioxidants, heat stabilizers, ultraviolet absorbers antistatic agents and surfactants. Moreover, a small amount of thermoplastic resin, for example, polyethylene, polypropylene, polyvinyl chloride, ABS resin, polystylene, methacrylic resin, polyamide, polyester, polyphenylene sulfide, polyetherketone, polyphenylene ether and a modifications thereof, polyether imide, can be added alone or in combination or two or more. Also a small amount of thermosetting resin, for example, phenol resin, epoxy resin, cyanate resin, isocyanate resin, polyimide resin can be added alone or in combination of two or more. A small amount of rubber component can also be added. The formulation method of the raw material for obtaining a resin composition of the present invention is not especially limited. Usually, an aromatic polycarbonate resin, an aromatic polysulfone resin, if necessary, reinforcements, such as glass fibers, inorganic fillers, mold release agent and a heat stabilizer, are mixed by using a Henschel mixer or a tumbling mixer and melt-kneaded using an extruder. As a method of melt-kneading, it is possible that all raw materials are mixed together and fed to an extruder. It is also possible that raw materials such as an inorganic filler and reinforcements like glass fibers are fed separately from raw materials mainly composed of resins. The preparation method of a molded article molded by using the thermoplastic resin composition of the present invention is not especially limited. As methods for melting, solidifying and shaping resins, extrusion molding, injection molding and blow molding, are mentioned. Among them, especially injection molding is used preferably. Further, the extrusion-molded article may be processed by cutting or pressing. The thermoplastic resin composition of the present invention can be used suitably for parts for e.g. cars or airplanes, industrial instruments, household electric appliances products, tablewares and medical instruments, OA/AV instruments, and electron/electronic parts ,for example, IC trays and IC sockets, for which especially heat resistance is needed. EXAMPLES The present invention will be illustrated by the following examples, which do not limit the scope of the present invention in any way. (1) Melt viscosity : Melt viscosity of an aromatic polycarbonate resin and an aromatic polysulfone resin used for the thermoplastic resin composition of the present invention is measured at a temperature of 340 °C, and a shear rate of 1216/second through an orifice having a diameter of 1mm, length of 10mm, by using TOYOSEIKI SEISAKUSHO Ltd. CAPIROGRAPH 1B. (2) Temperature of deflection under load (TDUL): A test piece (length of 127mm, width of 12.7mm and thickness of 6.4mm) is molded from a thermoplastic resin composition, using an injection molding machine, and measured according to ASTM D648, at the load of 18.6kg/cm 2 . (3) Tensile strength : ASTM dumbbell of No. 4 is molded from a thermoplastic resin composition using an injection molding machine, and measured according to ASTM D638. (4) Flexural modulus : A test piece (length of 127mm, width of 12.7mm and thickness of 6.4mm) is molded from a thermoplastic resin composition, using an injection molding machine, and measured according to ASTM D790. (5) Izod impact strength : A test piece for flexural modulus measurement (length of 127mm, width of 12.7mm, thickness of 6.4mm) is molded and divided into two pieces in equal size for Izod impact strength measurement. According to ASTM D-256, Izod impact strength is measured. (6) Heat resistance test in a microwave oven A square shape container (length of 147mm, width of 103mm, height of 30mm, and thickness of 1.5mm) is molded. 50g of salad oil(manufactured by The Nisshin Oil Mills, Ltd.) is put into the container. After irradiating the container for 10 minutes in a microwave oven(manufactured by Sharp Corporation, RE-HU0 type, output 65W), deformation of the container is evaluated as below. "Deformation" ; the bottom plane deformation in height is not less than 5mm. "Slight Deformation" ; although the bottom plane deformation in height is less than 5mm, shakiness has generated. (7) Surface smoothness Using a mold having a mirrorlike surface, a test piece (length of 64mm, width of 64mm and thickness of 1mm) is molded, and evaluated visually. (8) Lamp lighting test An article for lamp reflector (width of 150mm, height 100, depth of 50mm, and thickness of 1.5mm in the front side) is molded by injection molding. Aluminum deposition is applied to the article according to the above-described steps. The lamp reflector is equipped with a halogen lamp of 12V/55W, and after 240 hours lighting, the deformation degree is observed visually. Examples 1-3, Comparative examples 1-3 An aromatic polycarbonate resin (tradename CALIBRE, manufactured by Sumitomo Dow Limited), and an aromatic polysulfone resin (tradename SUMIKAEXCEL PES, manufactured by Sumitomo Chemical Co.,Ltd.) were mixed in a Henschel mixer as shown in Table 1, and pelletized at a cylinder temperature of 340 °C using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works, Ltd.), and a thermoplastic resin composition was obtained. A test piece was molded from this thermoplastic resin composition using an injection molding machine (PS40E5 ASE, manufactured by Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 350 °C, and a mold temperature of 120 °C. The evaluation result is shown in Table 1. Examples 4-8, Comparative example 4 Aromatic polycarbonate resins (tradename CALIBRE, manufactured by Sumitomo Dow Limited) having different melt viscosity, aromatic polysulfone resins (tradename SUMIKAEXCEL PES, manufactured by Sumitomo Chemical Co.,Ltd.) and carbon fibers (tradename BESFIGHT HTA-C6-CS, manufactured by Toho Rayon Co., Ltd.) were mixed as shown in Table 2 in a Henschel mixer, pelletized by using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works, Ltd.) at a cylinder temperature of 340 °C, and thermoplastic resin compositions were obtained. Test pieces were molded from the thermoplastic resin compositions by using an injection molding machine (PS40E5 ASE, manufactured by Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 350 °C, and a mold temperature of 120 °C. The evaluation result is shown in Table 2. Examples 9-11, Comparative Example5 Aromatic polycarbonate resins (tradename CALIBRE, manufactured by Sumitomo Dow Limited) having different melt viscosity , aromatic polysulfone resins (tradename SUMIKAEXCEL PES, manufactured by Sumitomo Chemical Co.,Ltd.) and glass fibers (tradename CS03JAPx-1, manufactured by Asahi Fiber Glass Co.,Ltd.) were mixed as shown in Table 3 in a Henschel mixer, pelletized by using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works, Ltd.) at a cylinder temperature of 340 °C, and thermoplastic resin compositions were obtained. Test pieces were molded from the thermoplastic resin compositions by using an injection molding machine (PS40E5 ASE, Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 350 °C, and a mold temperature of 120 °C. The evaluation result is shown in Table 3. Examples 12-18, Comparative examples 6 and 7 An aromatic polycarbonate resin (tradename CALIBRE, manufactured by Sumitomo Dow Limited), an aromatic polysulfone resin (tradename SUMIKAEXCEL PES, manufactured by Sumitomo Chemical Co.,Ltd.) and if necessary titan oxide (CR-60; average particle diameter of 0.2 µm, manufactured by Ishihara Sangyo Kaisha, Ltd.) were mixed in a Henschel mixer as shown in Table 4, and pelletized at a cylinder temperature of 340 °C using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works, Ltd.), and a thermoplastic resin composition was obtained. A test piece was molded from the thermoplastic resin composition by using an injection molding machine (PS40E5 ASE, manufactured by Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 350 °C, and a mold temperature of 120 °C. The evaluation result is shown in Table 4. It is found that the containers molded from the composition (comparative examples 6 and 7) having a low temperature of deflection under load, had a slight deformation by the above-mentioned microwave oven test and are inconvenient in practical use. Containers molded from the composition of examples 12-18 do not show neither deformation nor discoloration at all. Comparative examples 8 and 9 A microwave oven test was conducted using an aromatic poly sulfone resin in which n=m and p= 0 in the structure of the above-mentioned formula(II), (comparative example 8). Moreover, a polyether imide resin (tradename ULTEM1000, manufactured by General Electric Company), an aromatic polycarbonate resin (tradename CALIBRE, melt viscosity is 3500 poises at 340 °C under a shear rate of 1216/second, manufactured by Sumitomo Dow Limited,) and titanium oxide powder (tradename CR-60, mean particle diameter is 0.2 µm, manufactured by Ishihara Sangyo Kaisha, Ltd.) were mixed in the weight ratio of 70:30:10, pelletized, molded as the same manner with Example 1, and the microwave oven test was conducted (comparative examples 9). As a result, the container molded from the composition of comparative examples 8 shows deformation and discoloration. The container molded from the composition of comparative examples 9 shows a slight deformation and discoloration. Examples 19-29, Comparative examples 10 and 11 An aromatic polycarbonate resin (tradename CALIBRE, manufactured by Sumitomo Dow Limited), an aromatic polysulfone resin (tradename SUMIKAEXCEL PES, manufactured by Sumitomo Chemical Co.,Ltd.) and if neccesary, SP clay (rate of powders having a diameter of 20 µm or less is 98%, manufactured by Shokozan Mining Co.,Ltd.), CT kaolin (mean particle diameter of 1.6 µm, manufactured by Shokozan Mining Co.,Ltd.), Micron white #5000S which is talc with a mean particle diameter of 2.75 micrometers (manufactured by Hayashi Kasei Co., Ltd.) and CR-60 (manufactured by Ishihara Sangyo Kaisha, Ltd.) which is the titanium oxide powder whose mean particle diameter is 0.2 µm, were mixed in a Henschel mixer as shown in Table 5, and pelletized at a cylinder temperature of 340 °C using a twin-screw extruder (PCM-30, made by Ikegai Iron Works, Ltd.), and thermoplastic resin compositions were obtained. Test pieces were molded from the thermoplastic resin composition by using an injection molding machine (PS40E5 ASE, manufactured by Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 350 °C, and a mold temperature of 120 °C. The evaluation results are shown in Tables 5 and 6. Composition η a/η b Aromatic polycarbonate resin Aromatic polysulfone resin Filler (wt%) η a (poise) (wt%) η b (poise) (parts by weight) Example 19 30 3500 70 2200 - - 1.6 Example 20 40 3500 60 2200 - - 1.6 Example 21 30 3500 70 3700 - - 0.9 Example 22 40 3500 60 3700 - - 0.9 Example 23 30 3500 70 5300 - - 0.7 Example 24 30 3500 70 2200 Clay 5 1.6 Example 25 30 3500 70 2200 Clay 10 1.6 Example 26 30 3500 70 2200 Kaolin 5 1.6 Example 27 30 3500 70 2200 Kaolin 10 1.6 Example 28 30 3500 70 2200 Talc 5 1.6 Example 29 30 3500 70 2200 Talc 10 1.6 Comparative Example 10 60 3500 40 2200 - - 1.6 Comparative Example 11 40 1400 60 3700 - - 0.4 Tensile Strength (kg/cm 2 ) Flexural Modulus (kg/cm 2 ) Izod Impact strength TDUL (°C) Surface Smoothness Lighting test Example 19 780 25700 >160 191 good no deformation Example 20 770 25100 >160 190 good no deformation Example 21 790 25700 >160 186 good no deformation Example 22 760 25100 >160 185 good no deformation Example 23 800 25800 >160 182 good no deformation Example 24 770 31000 >160 197 good no deformation Example 25 770 35400 95 198 good no deformation Example 26 780 30100 >160 195 good no deformation Example 27 790 34000 88 195 good no deformation Example 28 780 31200 >160 198 good no deformation Example 29 790 35600 91 199 good no deformation Comparative Example 10 760 25000 >160 153 silver slight deformation Comparative Example 11 770 26100 >160 154 good slight deformation The reflectors molded from the composition of the comparative examples 10 and 11 show a slight deformation after lamp lighting test, and are inconvenient in practical use. With the reflectors molded from the composition of examples 19-23, neither deformation nor discoloration was observed at all. The reflectors molded from the compositions(examples 24-29) which contain clay, kaolin, talc, or titanium oxide in the thermoplastic resin composition comprising an aromatic polycarbonate resin and an aromatic polysulfone resin, neither show deformation nor discoloration at all. Comparative examples 12 and 13 A microwave oven test was conducted using an aromatic poly sulfone resin in which n=m and p= 0 in the structure of the above-mentioned formula(II),(comparative example 12). Moreover, a polyether imide resin (tradename ULTEM1000, manufactured by General Electric Company) and an aromatic polycarbonate resin (tradename CALIBRE, melt viscosity is 3500 poises at 340 °C under a shear rate of 1216/second, manufactured by Sumitomo Dow Limited) were mixed in the weight ratio of 70:30, pelletized, molded, and the lamp lighting test was conducted (comparative examples 13). As a result, the reflector molded from the composition of comparative examples 12 shows deformation. The reflector molded from the composition of comparative examples 13 also shows slight deformation. The thermoplastic resin composition and the molded article of the present invention are excellent in heat resistance and mechanical and physical properties. They are very effective when used for parts, such as cars and airplanes, industrial instruments, household electric appliances products, tablewares and medical instruments, OA/AV instruments, electron/electronic parts, especially for uses such as a lamp reflector, microwave oven parts, the IC tray, and an IC socket in which heat resistance is needed.

Claims: A thermoplastic resin composition comprising 25 to 45% by weight of an aromatic polycarbonate resin, and 75 to 55% by weight of an aromatic polysulfone resin consisting of the repeating unit represented by the following formula wherein the ratio (ηa/ηb) of the melt viscosity (ηa) of the aromatic polycarbonate resin to the melt viscosity (ηb) of the aromatic polysulfone resin defined below is 0.5 to 2.0, wherein ηa is the melt viscosity of the aromatic polycarbonate resin measured at a temperature of 340°C and a shear rate of 1216/second through an orifice having a diameter of 1 mm and a length of 10 mm, ηb is the melt viscosity of the aromatic polysulfone resin measured at a temperature of 340°C and a shear rate of 1216/second through an orifice having a diameter of 1 mm and a length of 10 mm, and ηa is in the range of from 2,000 to 10,000 poises, and ηb is in the range of from 1,000 to 6,000. The thermoplastic resin composition comprising 100 parts by weight of the thermoplastic resin composition of claim 1, and 1 to 10 parts by weight of titanium oxide having a number average particle diameter of 0.01 to 5 µm. The thermoplastic resin composition comprising 100 parts by weight of the thermoplastic resin compositions of claim 1, and 1 to 80 parts by weight of a filler selected from the group consisting of clay, kaolin and talc. The thermoplastic resin composition according to claim 1, 2 or 3, wherein the ratio (ηa/ηb) is 0.8 to 1.8. The thermoplastic resin composition according to claim 1, 2 or 3, wherein the aromatic polycarbonate resin is a co-polycarbonate or a homo-polycarbonate containing at least 30 mol% of bisphenol A unit. A molded article obtainable from the thermoplastic resin composition of claim 1,2 or 3. Microwave oven parts molded by using the thermoplastic resin composition of claim 1 or 2, wherein said parts are an axial receptacle, a rotational gear, a saucer or a container for food cooking for use in a microwave oven. The microwave oven parts according to claim 7, wherein the parts are a saucer or a container for food cooking for use in a microwave oven. A lamp reflector comprising the thermoplastic resin composition of claim 1 or 3. The lamp reflector according to claim 9, wherein the lamp reflector is a head lamp for cars, a reflector for fog lamps or a sub-reflector for head lamps.

Inventors: MAEDA MITUO, NAGASHIMA TOHRU, NAKAMURA HIROSHI, NOMURA HIDEO, MAEDA, MITUO, NAGASHIMA, TOHRU, NAKAMURA, HIROSHI, NOMURA, HIDEO
Applicants: SUMITOMO CHEMICAL CO, SUMITOMO CHEMICAL COMPANY, LIMITED
Application year: 1997
Main classification: C08L81
IPC codes: C08L69, C08L81