Automotive interior parts

Abstract

An automotive interior part includes a thermoplastic resin composition containing a prescribed acetone insoluble fraction (A) and a prescribed acetone soluble fraction (B), in which a content of the acetone insoluble fraction (A) is 5 to 18% by mass based on 100% by mass of a sum of the acetone insoluble fraction (A) and the acetone soluble fraction (B).

Claims

1. An automotive interior part, comprising a thermoplastic resin composition comprising an acetone insoluble fraction (A) and an acetone soluble fraction (B), wherein a content of the acetone insoluble fraction (A) is 5 to 18% by mass based on 100% by mass of a sum of the acetone insoluble fraction (A) and the acetone soluble fraction (B), the acetone insoluble fraction (A) comprises one, two or more resins having different constitutional units, the constitutional units of all the resins comprised in the acetone insoluble fraction (A) comprise at least a rubber component unit having a mass average particle size of 0.1 to 0.35 μm, an aromatic vinyl monomer unit and an unsaturated nitrile monomer unit, the acetone insoluble fraction (A) comprises a graft copolymer in which at least the unsaturated nitrile monomer unit is grafted onto the rubber component unit, a content of the unsaturated nitrile monomer unit comprised in the graft copolymer is 15 to 28% by mass based on 100% by mass of all grafted constitutional units, the acetone soluble fraction (B) comprises one, two or more resins having different constitutional units, and the constitutional units of all the resins comprised in the acetone soluble fraction (B) comprise at least an aromatic vinyl monomer unit, an unsaturated nitrile monomer unit, a methacrylate monomer unit and a maleimide-based monomer unit, and a content of the methacrylate monomer unit is 45 to 60% by mass based on 100% by mass of the constitutional units of all the resins comprised in the acetone soluble fraction (B).

2. The automotive interior part according to claim 1, wherein a Vicat softening point according to ISO 306 of the thermoplastic resin composition is 105 to 120° C.

3. The automotive interior part according to claim 1, wherein a content of the maleimide-based monomer unit is 5 to 13% by mass based on 100% by mass of the thermoplastic resin composition.

4. The automotive interior part according to claim 1, wherein the rubber component unit comprises a diene-based rubber unit.

5. The automotive interior part according to claim 1, wherein a content of the rubber component unit is 30 to 60% by mass based on 100% by mass of the constitutional units of all the resins comprised in the acetone insoluble fraction (A).

Description

EXAMPLES

(1) The present embodiment will now be more specifically described with reference to Examples, and it is noted that the present embodiment is not limited thereto.

(2) (1) Method for Extracting Acetone Insoluble Fraction

(3) The content of an acetone insoluble fraction contained in an injection molded product was checked by the following method. Two dry centrifuge tubes were prepared for each sample, and after cooling the centrifuge tubes in a desiccator for 15 minutes or more, the tubes were precisely weighed up to 0.1 mg by an electric balance. A sample of about 1 g cut out from the injection molded product was weighed into each centrifuge tube, and the resultant tube was precisely weighed up to 0.1 mg. About 20 mL of acetone was collected by a measuring cylinder and put into each centrifuge tube, and the resultant centrifuge tube was sealed with a silicone stopper and shaken by a shaker for 2 hours. After shaking, a portion of the sample adhering to the silicone stopper was dropped off into the centrifuge tube by using a small amount of acetone. The resultant two centrifuge tubes were set on a diagonal line in a rotor of a Hitachi high speed cooling centrifuge, and the centrifuge was operated for performing centrifugation at a rotational speed of 20000 rpm for 60 minutes.

(4) After completing the centrifugation, each precipitation tube was taken out of the rotor, a supernatant was decanted. About 20 mL of acetone was collected by a measuring cylinder and put into each centrifuge tube, and the resultant centrifuge tube was sealed with a silicone stopper and then shaken by a shaker for 1 hour. An operation of decanting a supernatant thus obtained (after the shaking for 1 hour), and thereafter, putting about 20 mL of acetone thereto again and shaking the resultant for 1 hour was repeated once again, and then, the resultant was centrifuged at a rotational speed of 20000 rpm for 50 minutes.

(5) After completing the centrifugation, each precipitation tube was taken out of the rotor, and a supernatant was decanted. Thereafter, an operation similar to the second decantation was carried out again.

(6) After completing the centrifugation, about 20 mL of acetone was collected by a measuring cylinder and put into each centrifuge tube, and the resultant centrifuge tube was sealed with a silicone stopper and then centrifuged at a rotational speed of 20000 rpm for 30 minutes. After completing the centrifugation, each precipitation tube was taken out of the rotor, and a supernatant was decanted. The thus obtained precipitate was dried at 80° C. for 30 minutes, and then at 130° C. for 30 minutes, and thus, an acetone insoluble fraction was obtained.

(7) (1-2) Method for Extracting Acetone Soluble Fraction

(8) A supernatant decanted in the above-described method was collected, and an acetone component was removed therefrom by vaporization to obtain an acetone soluble fraction.

(9) (1-3) Method for Measuring Content of Acetone Insoluble Fraction

(10) After the drying, the resultant was cooled in a desiccator for 30 minutes or more. After sufficiently cooling, the resultant acetone insoluble fraction was precisely weighed up to 0.1 mg by an electric balance. The content (% by mass) of the acetone insoluble fraction based on 100% by mass of a sum of the acetone insoluble fraction (A) and the acetone soluble fraction (B) was calculated in accordance with the following expression:
Content (% by mass) of Acetone insoluble fraction=[Amount (g) of acetone insoluble fraction/Amount (g) of collected sample]×100

(11) If the injection molded product contained an inorganic insoluble fraction, the content (% by mass) of the acetone insoluble fraction based on 100% by mass of the sum of the acetone insoluble fraction (A) and an acetone soluble fraction (B) was calculated in accordance with the following expression:
Acetone insoluble fraction (% by mass)=[(Acetone insoluble fraction containing inorganic insoluble fraction (% by mass)−Inorganic insoluble fraction (% by mass))/(100−Inorganic insoluble fraction (% by mass))]×100

(12) Here, the term “inorganic insoluble fraction” refers to titanium, glass fiber, talc, calcium carbonate or the like used in, for example, a coloring pigment.

(13) (2) Mass Average Particle Size of Rubber Component Unit

(14) The acetone insoluble fraction (A) was extracted from the injection molded product, and an ultra-thin section of 60 nm±2 nm was cut out therefrom. The ultra-thin section was dyed with osmic acid, and the resultant was observed with a transparent electron microscope (TEM; manufactured by Hitachi High-Technologies Corporation, product name: H-600AB). The thus obtained TEM photograph was analyzed by using image analysis software (manufactured by Asahi Kasei Engineering Corporation, product name: A-Zo Kun), and thus, a mass average particle size of a rubber component unit was obtained.

(15) (3) Content of Methacrylate Monomer Unit

(16) The composition of the acetone soluble fraction (B) was analyzed by pyrolysis gas chromatography, so as to calculate a content of a methyl methacrylate unit based on 100% by mass of constitutional units of all resins contained in the acetone soluble fraction (B).

(17) (4) Content of Unsaturated Nitrile Monomer Unit Contained in Graft Copolymer

(18) The composition of the acetone insoluble fraction (A) was analyzed by using a Fourier transform infrared spectrometer (FT-IR; manufactured by Perkin Elmer Co., Ltd, product name: Spectrum One), so as to calculate a content of an unsaturated nitrile monomer unit contained in a graft copolymer based on 100% by mass of all grafted constitutional units.

(19) (5) Graft Ratio (%)

(20) A graft ratio (%) of a graft copolymer described below was obtained by analysis of an absorption peak obtained by using the Fourier transform infrared spectrometer (FT-IR).

(21) (6) Reduced Viscosity (dl/g)

(22) A reduced viscosity (dl/g) of a copolymer described below was measured by the following method.

(23) A thermoplastic resin was dissolved in acetone, and the resultant was separated by a centrifuge into an acetone soluble fraction and an acetone insoluble fraction. A reduced specific viscosity of a component of the thermoplastic resin not grafted onto a rubber-like polymer (a non-grafted component) was obtained by measuring a flowing time taken by a solution obtained by dissolving 0.25 g of the acetone soluble fraction in 50 ml of 2-butanone to flow through a Cannon-Fenske type capillary at 30° C.

(24) (7) Weight Average Molecular Weight (Mw) of Methacrylic-Based Copolymer

(25) A weight average molecular weight (Mw) of a methacrylic-based copolymer was measured by gel permeation chromatography (GPC; manufactured by Tosoh Corporation, product name: HLC-8220GPC). As specific conditions, separation columns manufactured by Tosoh Corporation (three TSKgel-GMH.sub.XL columns) were used for performing the chromatography at a temperature of 38° C., by using tetrahydrofuran as a solvent, with a sample concentration set to 0.1 wt/v %, and a sampling pitch set to 1/0.4 (times/sec). A molecular weight of a separated component was calculated by creating a calibration curve, as a cubic regression curve, of the relationship between a molecular weight and an elution time of TSK standard polystyrene manufactured by the same company. A content of a specific molecular weight was calculated on the basis of an area ratio. A peak top molecular weight refers to a molecular weight corresponding to an elution time having a largest peak height.

(26) (8) Jet-Blackness (Brightness (L*))

(27) Brightness (L*) on a surface of an injection molded product was measured under geometric condition C (de: 8°) according to JIS 28722. For measuring the brightness (L*), a spectrophotometer “CM-2002” (manufactured by Konica Minolta, Inc.) was used. As specific conditions, a light source D65 was used, luminous flux φ was set to 11 mm, and a view angle was set to 10°. A sample was not especially limited, and a comparatively smooth portion of the injection molded product was used.

(28) (9) Heat Resistance (Vicat Softening Point)

(29) Heat resistance was measured by using an injection molded product by a method B-120 according to ISO 306. A load was set to 50N, and a temperature increasing speed was set to 120° C./h. A sample had a size of about 20 to 30 mm (in width)×20 to 30 mm (in length)×2 to 4 mm (in thickness). If a sample had a thickness smaller than 2 mm, several samples stacked on one another may be used.

(30) (10) Impact Resistance (Charpy Impact Value)

(31) An injection molding machine (manufactured by Toshiba Machine Co., Ltd., product name: EC100S) was used to mold a multi-purpose test specimen type-A (ISO dumbbell test specimen) with a thickness of 4 mm in accordance with ISO 294 at a cylinder temperature of 250° C. and a mold temperature of 60° C., and the obtained test specimen was processed into a shape of 80 mm×10 mm×4 mm, and thereafter, the resultant specimen was notched with a prescribed size in accordance with ISO 179 and then subjected to a test. As a test value, an average of values obtained in five test specimens was used.

(32) (11) Mass Decrease Ratio

(33) A pellet was used for measuring a mass decrease ratio by TGA “MTC 1000SA” and “TG-DTA 2000SR” (manufactured by Bruker). Specifically, it was dried at 90° C. for 4 hours to remove a water content, and then, the temperature was increased at 100° C./min up to 260° C., and after standing still at 260° C. for 30 minutes, a mass was measured. A mass decrease ratio was calculated in accordance with the following expression assuming that a mass (m1) before the test was 100% and that a mass after the test was a mass (m2):
Mass decrease ratio (%)=100−m2/m1×100

(34) It is noted that the temperature increasing speed and the like are not especially limited, and the temperature is preferably increased at 100° C./min.

(35) (12) Scratch Resistance (Pencil Hardness)

(36) An injection molded product was used for measuring the scratch resistance according to JIS K5400.

(37) (13) Appearance Properties (White Haze)

(38) An injection molded product was wholly visually checked. If there were no irregularities and cloud in color tone, it was evaluated as ◯, if they could be recognized at a distance of 100 mm, it was evaluated as Δ, and if they could be recognized at a distance of 500 mm, it was evaluated as X.

(39) (14) Appearance Properties (Silver Streaks)

(40) The surface of an injection molded product was observed at 270° C. If no silver streaks was recognized, it was evaluated as ◯, if it could be recognized at a distance of 100 mm, it was evaluated as Δ, and if it could be recognized at a distance of 500 mm, it was evaluated as X.

(41) (1) Raw Materials Used

Preparation Example 1 of Graft Copolymer

(42) A polymerization reaction vessel was charged with 110 parts by mass of a polybutadiene rubber latex (having a mass average particle size, measured by using a micro-track particle size analyzer “nanotrac 150” manufactured by Nikkiso Co., Ltd., of 0.25 μm, a solid content of 50% by mass, and a moisture index of 40%), 0.1 parts by mass of tertiary dodecyl mercaptan, and 25 parts by mass of deionized water, and after a gas phase portion was replaced with nitrogen, the temperature was increased to 55° C. Subsequently, while increasing the temperature up to 70° C. over 1.5 hours, a monomer mixture solution containing 12 parts by mass of acrylonitrile, 48 parts by mass of styrene, 0.5 parts by mass of tertiary dodecyl mercaptan and 0.15 parts by mass of cumene hydroperoxide, and an aqueous solution obtained by dissolving, in 22 parts by mass of deionized water, 0.2 parts by mass of sodium formaldehyde sulfoxylate, 0.004 parts by mass of ferrous sulfate and 0.04 parts by mass of disodium ethylenediaminetetraacetate were added thereto over 4 hours. After completing the addition, the polymerization reaction was completed while controlling the polymerization reaction vessel at 70° C. for 1 hour.

(43) To the thus obtained ABS latex, an antifoaming agent made of a silicone resin (manufactured by Momentive Performance Materials Japan Inc., product name: TSA737, the same shall apply hereinafter) and a phenol-based antioxidant emulsion (manufactured by Chukyo Yushi Co., Ltd., product name: L-673, the same shall apply hereinafter) were added, and an aluminum sulfate aqueous solution was further added thereto to cause coagulation, and the resultant was sufficiently dehydrated, washed with water and then dried, and thus, a graft copolymer (A-1) was obtained. Here, a vinyl-based copolymer (B-1), that is, a thermoplastic resin, was simultaneously obtained. The graft copolymer (A-1) and the vinyl-based copolymer (B-1) were in a ratio of 74.9% by mass and 25.1% by mass. Results obtained by analyzing the graft copolymer (A-1) and the vinyl-based copolymer (B-1) are shown in Table 1.

Preparation Example 2 of Graft Copolymer

(44) A polymerization reaction vessel was charged with 110 parts by mass of a polybutadiene rubber latex (having a mass average particle size, measured by using a micro-track particle size analyzer “nanotrac 150” manufactured by Nikkiso Co., Ltd., of 0.32 μm, a solid content of 50% by mass, and a moisture index of 40%), 0.1 parts by mass of tertiary dodecyl mercaptan, and 25 parts by mass of deionized water, and after a gas phase portion was replaced with nitrogen, the temperature was increased to 55° C. Subsequently, while increasing the temperature up to 70° C. over 1.5 hours, a monomer mixture solution containing 16.2 parts by mass of acrylonitrile, 43.8 parts by mass of styrene, 0.5 parts by mass of tertiary dodecyl mercaptan and 0.15 parts by mass of cumene hydroperoxide, and an aqueous solution obtained by dissolving, in 22 parts by mass of deionized water, 0.2 parts by mass of sodium formaldehyde sulfoxylate, 0.004 parts by mass of ferrous sulfate and 0.04 parts by mass of disodium ethylenediaminetetraacetate were added thereto over 4 hours. After completing the addition, the polymerization reaction was completed while controlling the polymerization reaction vessel at 70° C. for 1 hour.

(45) To the thus obtained ABS latex, an antifoaming agent made of a silicone resin and a phenol-based antioxidant emulsion were added, and an aluminum sulfate aqueous solution was further added thereto to cause coagulation, and the resultant was sufficiently dehydrated, washed with water and then dried, and thus, a graft copolymer (A-2) was obtained. Here, a vinyl-based copolymer (B-2), that is, a thermoplastic resin, was simultaneously obtained. The graft copolymer (A-2) and the vinyl-based copolymer (B-2) were in a ratio of 75.0% by mass and 25.0% by mass. Results obtained by analyzing the graft copolymer (A-2) and the vinyl-based copolymer (B-2) are shown in Table 1.

Preparation Example 3 of Graft Copolymer

(46) A polymerization reaction vessel was charged with 110 parts by mass of a polybutadiene rubber latex (having a mass average particle size, measured by using a micro-track particle size analyzer “nanotrac 150” manufactured by Nikkiso Co., Ltd., of 0.32 μm, a solid content of 50% by mass, and a moisture index of 40%), 0.1 parts by mass of tertiary dodecyl mercaptan, and 25 parts by mass of deionized water, and after a gas phase portion was replaced with nitrogen, the temperature was increased to 55° C. Subsequently, while increasing the temperature up to 70° C. over 1.5 hours, a monomer mixture solution containing 18 parts by mass of acrylonitrile, 42 parts by mass of styrene, 0.5 parts by mass of tertiary dodecyl mercaptan and 0.15 parts by mass of cumene hydroperoxide, and an aqueous solution obtained by dissolving, in 22 parts by mass of deionized water, 0.2 parts by mass of sodium formaldehyde sulfoxylate, 0.004 parts by mass of ferrous sulfate and 0.04 parts by mass of disodium ethylenediaminetetraacetate were added thereto over 4 hours. After completing the addition, the polymerization reaction was completed while controlling the polymerization reaction vessel at 70° C. for 1 hour.

(47) To the thus obtained ABS latex, an antifoaming agent made of a silicone resin and a phenol-based antioxidant emulsion were added, and an aluminum sulfate aqueous solution was further added thereto to cause coagulation, and the resultant was sufficiently dehydrated, washed with water and then dried, and thus, a graft copolymer (A-3) was obtained. Here, a vinyl-based copolymer (B-3), that is, a thermoplastic resin, was simultaneously obtained. The graft copolymer (A-3) and the vinyl-based copolymer (B-3) were in a ratio of 75.0% by mass and 25.0% by mass. Results obtained by analyzing the graft copolymer (A-3) and the vinyl-based copolymer (B-3) are shown in Table 1.

Preparation Example 4 of Graft Copolymer

(48) A polymerization reaction vessel was charged with 110 parts by mass of a polybutadiene rubber latex (having a mass average particle size, measured by using a micro-track particle size analyzer “nanotrac 150” manufactured by Nikkiso Co., Ltd., of 0.37 μm, a solid content of 50% by mass, and a moisture index of 40%), 0.1 parts by mass of tertiary dodecyl mercaptan, and 25 parts by mass of deionized water, and after a gas phase portion was replaced with nitrogen, the temperature was increased to 55° C. Subsequently, while increasing the temperature up to 70° C. over 1.5 hours, a monomer mixture solution containing 18 parts by mass of acrylonitrile, 42 parts by mass of styrene, 0.5 parts by mass of tertiary dodecyl mercaptan and 0.15 parts by mass of cumene hydroperoxide, and an aqueous solution obtained by dissolving, in 22 parts by mass of deionized water, 0.2 parts by mass of sodium formaldehyde sulfoxylate, 0.004 parts by mass of ferrous sulfate and 0.04 parts by mass of disodium ethylenediaminetetraacetate were added thereto over 4 hours. After completing the addition, the polymerization reaction was completed while controlling the polymerization reaction vessel at 70° C. for 1 hour.

(49) To the thus obtained ABS latex, an antifoaming agent made of a silicone resin and a phenol-based antioxidant emulsion were added, and an aluminum sulfate aqueous solution was further added thereto to cause coagulation, and the resultant was sufficiently dehydrated, washed with water and then dried, and thus, a graft copolymer (A-4) was obtained. Here, a vinyl-based copolymer (B-4), that is, a thermoplastic resin, was simultaneously obtained. The graft copolymer (A-4) and the vinyl-based copolymer (B-4) were in a ratio of 74.9% by mass and 25.1% by mass. Results obtained by analyzing the graft copolymer (A-4) and the vinyl-based copolymer (B-4) are shown in Table 1.

Preparation Example 1 of Vinyl-Based Copolymer

(50) A mixture of 13 parts by mass of acrylonitrile, 52 parts by mass of styrene, 35 parts by mass of toluene serving as a solvent, and 0.05 parts by mass of t-butylperoxy-2-ethylhexanoate serving as a polymerization initiator was bubbled with a nitrogen gas, and the resultant was then supplied, continuously at a speed of 37.5 kg/h, by using a spray nozzle into a reaction vessel having an internal volume of 150 L equipped with a two-stage inclined paddle type (having an inclination angle of 45 degrees) impeller similar to that described in Example 2 of Japanese Patent No. 3664576.

(51) A polymerization temperature was set to 130° C., and a reaction liquid in the same amount as a supply liquid was continuously drawn out so that a filling rate of the reaction liquid in the reaction vessel could be retained at 70% by volume. A portion of the reaction vessel corresponding to a liquid phase portion was provided with a jacket for controlling the temperature, and the jacket temperature was set to 128° C.

(52) The drawn reaction liquid was introduced into a volatile removal apparatus kept at 250° C. and a high vacuum of 10 mmHg, so as to collect an unreacted monomer and an organic solvent by degassing and to collect the generated vinyl-based copolymer (B-5) as a pellet. Results obtained by analyzing the vinyl-based copolymer (B-5) are shown in Table 1.

Preparation Example 2 of Vinyl-Based Copolymer

(53) A vinyl-based copolymer (B-6) was prepared in the same manner as in Preparation Example 1 of Vinyl-based Copolymer except that 16 parts by mass of acrylonitrile, 49 parts by mass of styrene, 35 parts by mass of toluene serving as a solvent and 0.05 parts by mass of t-butylperoxy-2-ethylhexanoate serving as a polymerization initiator were used, and that the temperature of the temperature-controlling jacket was set to 129° C.

(54) The drawn reaction liquid was introduced into a volatile removal apparatus kept at 250° C. and a high vacuum of 10 mmHg, so as to collect an unreacted monomer and an organic solvent by degassing and to collect the generated vinyl-based copolymer (B-6) as a pellet. Results obtained by analyzing the vinyl-based copolymer (B-6) are shown in Table 1.

Preparation Example 3 of Vinyl-Based Copolymer

(55) A vinyl-based copolymer (B-7) was prepared in the same manner as in Preparation Example 1 of Vinyl-based Copolymer except that 21 parts by mass of acrylonitrile, 47 parts by mass of styrene, 32 parts by mass of toluene serving as a solvent and 0.05 parts by mass of t-butylperoxy-2-ethylhexanoate serving as a polymerization initiator were used, and that the temperature of the temperature-controlling jacket was set to 128° C.

(56) The drawn reaction liquid was introduced into a volatile removal apparatus kept at 250° C. and a high vacuum of 10 mmHg, so as to collect an unreacted monomer and an organic solvent by degassing and to collect the generated vinyl-based copolymer (B-7) as a pellet. Results obtained by analyzing the vinyl-based copolymer (B-7) are shown in Table 1.

Preparation Example 1 of Methacrylic-Based Copolymer

(57) A vessel having a stirrer equipped with four inclined paddle impeller s was charged with 2 kg of water, 65 g of tribasic calcium phosphate, 39 g of calcium carbonate and 0.39 g of sodium lauryl sulfate to obtain a mixed solution. Next, a 60-L reactor having a stirrer equipped with three backward swept impellers was charged with 26 kg of water, the temperature was increased to 80° C., and then, the reactor was charged with the mixed solution, 19,042 g of methyl methacrylate, 1,393 g of styrene, 2,787 g of N-phenylmaleimide, 40.64 g of lauroyl peroxide and 48.77 g of n-octyl mercaptan. The temperature was kept at about 75° C. for performing suspension polymerization, and an exothermic peak was observed about 120 minutes after introducing the raw materials. Thereafter, the temperature was increased to 93° C. at a speed of 1° C./min, the reaction solution was then aged for 120 minutes, and the polymerization reaction was substantially completed. Next, the temperature was lowered to 50° C., and 20% by mass of sulfuric acid was introduced to dissolve a suspension agent. Subsequently, after the polymerization reaction solution was allowed to pass through a 1.68 mm mesh sieve to remove aggregate, a water component was filtered out, the resultant slurry was dehydrated to obtain a bead-shaped polymer, the thus obtained bead-shaped polymer was washed with water, then dehydrated as described above, further washed by repeating washing with ion-exchanged water and dehydrating, and thus, a methacrylic-based copolymer (M-1) was obtained. The thus obtained methacrylic-based copolymer (M-1) was a methyl methacrylate-N-phenylmaleimide-styrene copolymer. Results obtained by analyzing the methacrylic-based copolymer (M-1) are shown in Table 1.

Preparation Example 2 of Methacrylic-Based Copolymer

(58) A methacrylic-based copolymer (M-2) was prepared in the same manner as in Preparation Example 1 of Methacrylic-based Copolymer except that 18,578 g of methyl methacrylate, 1,161 g of styrene, 3,019 g of N-phenylmaleimide, 464 g of methyl acrylate, 40.32 g of lauroyl peroxide and 47.32 g of n-octyl mercaptan were used. The thus obtained methacrylic-based copolymer (M-2) was a methyl methacrylate-methyl acrylate-N-phenylmaleimide-styrene copolymer. Results obtained by analyzing the methacrylic-based copolymer (M-2) are shown in Table 1.

Preparation Example 3 of Methacrylic-Based Copolymer

(59) A methacrylic-based copolymer (M-3) was prepared in the same manner as in Preparation Example 1 of Methacrylic-based Copolymer except that 1,523 g of methyl methacrylate, 284 g of styrene, 163 g of maleic anhydride, 0.99 g of lauroyl peroxide and 4.93 g of n-octyl mercaptan were used. The thus obtained methacrylic-based copolymer (M-3) was a methyl methacrylate-styrene-maleic anhydride copolymer. Results obtained by analyzing the methacrylic-based copolymer (M-3) are shown in Table 1.

Preparation Example 4 of Methacrylic-Based Copolymer

(60) A methacrylic-based copolymer (M-4) was prepared in the same manner as in Preparation Example 1 of Methacrylic-based Copolymer except that 22,440 g of methyl methacrylate, 694 g of methyl acrylate, 46.27 g of lauroyl peroxide and 55.52 g of n-octyl mercaptan were used. The thus obtained methacrylic-based copolymer (M-4) was a methyl methacrylate-methyl acrylate copolymer. Results obtained by analyzing the methacrylic-based copolymer (M-4) are shown in Table 1.

Preparation Example 5 of Methacrylic-Based Copolymer

(61) A methacrylic-based copolymer (M-5) was prepared in the same manner as in Preparation Example 1 of Methacrylic-based Copolymer except that 14,482 g of methyl methacrylate, 2,758 g of styrene, 5,747 g of N-phenylmaleimide, 34.48 g of lauroyl peroxide and 43.68 g of n-octyl mercaptan were used. The thus obtained methacrylic-based copolymer (M-5) was a methyl methacrylate-N-phenylmaleimide-styrene copolymer. Results obtained by analyzing the methacrylic-based copolymer (M-5) are shown in Table 1.

Example 1 of Alternative Coloring Agent

(62) Mitsubishi carbon black #850 (X-1) (trade name) (carbon black manufactured by Mitsubishi Chemical Corporation, having a sublimation temperature of 3642° C.)

Example 1

(63) Fifteen parts by mass of the graft copolymer (A-1), 5 parts by mass of the vinyl-based copolymer (B-1), 15 parts by mass of the vinyl-based copolymer (B-5), 5 parts by mass of the vinyl-based copolymer (B-6), 60 parts by mass of the methacrylic-based copolymer (M-1) and 0.5 parts by mass of the coloring agent (X-1) were mixed, the resultant mixture was introduced into a hopper of a twin screw extruder (“ZSK-25” manufactured by Coperion), and a pellet was produced at a cylinder set temperature of 250° C., a screw rotational speed of 200 rpm, and a discharge rate of 10 kg/hr. The thus produced pellet was subjected to injection molding (“EC100” manufactured by Toshiba Machine Co., Ltd.) at a resin temperature of 250° C., a mold temperature of 70° and an injection speed of 20 mm/s, and thus, an injection molded product in a plate shape of 50 mm×90 mm×2.5 mm was produced. Incidentally, for checking silver streaks, an injection molded product was produced in the same manner as in the production of the plate except that the resin temperature was set to 270° C.

Examples 2 to 6 and Comparative Examples 1 to 7

(64) Pellets and injection molded products were obtained in the same manner as in Example 1 by employing compositions listed in Table 2.

(65) TABLE-US-00001 TABLE 1 Graft Copolymer A-1 A-2 A-3 A-4 Acrylonitrile (wt %) 6.7 9 10 8.3 Butadiene (wt %) 66.8 66.7 66.7 66.8 Styrene (wt %) 26.5 24.3 23.3 24.9 Graft Ratio (wt %) 49.7 49.9 49.9 49.7 Mass Average Particle 0.25 0.32 0.32 0.37 Size of Rubber Component Unit Content of Unsaturated 20 27 30 25 Nitrile Monomer in Graft (wt %) Vinyl-based Copolymer B-1 B-2 B-3 B-4 B-5 B-6 B-7 Acrylonitrile (wt %) 20.1 27 30 25.1 20.8 24.8 29.8 Styrene (wt %) 79.9 73 70 74.9 79.2 75.2 70.2 Reduced Viscosity 0.33 0.34 0.33 0.33 0.67 0.46 0.65 (dl/g) Methacrylic-based Copolymer M-1 M-2 M-3 M-4 M-5 Methyl Methacrylate 82 80 77 97 63 (wt %) Methyl Acrylate (wt %) — 2 — 3 — N-Phenylmaleimide 12 13 — — 25 (wt %) Styrene (wt %) 6 5 15 — 12 Maleic Anhydride (wt %) — — 8 — — Weight Average 120000 130000 120000 100000 130000 Molecular Weight (Mw)

(66) TABLE-US-00002 TABLE 2 Comparative Examples Examples 1 2 3 4 5 6 1 2 Graft Copolymer A-1 15.0 15.0 3.0 18.0 3.0 3.0 A-2 15.0 3.0 3.0 A-3 15.0 A-4 Mass Average Particle Size of μm 0.25 0.32 0.25 0.29 0.25 0.29 0.25 0.32 Rubber Component Unit ontent of Unsaturated Nitrile mass % 20.0 27.0 20.0 23.5 20.0 23.5 20.0 30.0 Monomer in Graft Vinyl-based Copolymer B-1 5.0 5.0 5.0 1.0 6.5 1.0 1.0 B-2 1.0 1.0 B-3 5.0 B-4 B-5 15.0 15.0 B-6 5.0 5.0 30.0 32.0 19.0 21.5 36.0 10.0 B-7 10.0 Methacrylic-based Copolymer M-1 60.0 60.0 60.0 55.0 60.0 60.0 M-2 50.0 70.5 M-3 M-4 M-5 Coloring Agent X-1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Acetone Insoluble Fraction (A) mass % 15.0 15.0 15.0 6.0 18.0 6.0 3.0 15.0 Acetone Soluble Fraction (B) mass % 85.0 85.0 85.0 94.0 82.0 94.0 97.0 85.0 Ratio of Methacrylate Monomer mass % 57.9 57.9 47.1 52.3 55.0 60.0 50.7 57.9 (in Acetone Soluble Fraction) Ratio of Maleimide-based mass % 7.2 7.2 6.5 7.2 6.6 9.2 7.2 7.2 Monomer Unit in 100 mass % of Thermoplastic Resin Composition Vicat Softening Point ° C. 119 119 115 119 117 121 119 119 Charpy Impact J/m2 9 10 10 4 12 4 1 8 Brightness (L*) — 5.9 5.9 6.2 5.7 6.4 6.2 5.7 6.5 Appearance Properties/Silver — ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ streaks Appearance Properties/White Haze — ◯ ◯ ◯ ◯ ◯ ◯ ◯ X Mass decrease ratio % 0.8 0.8 0.8 0.8 0.7 0.9 0.8 0.8 Pencil Hardness — F F F H HB H H F Comparative Examples 3 4 5 6 7 Graft Copolymer A-1 25.5 15.0 15.0 15.0 A-2 A-3 A-4 15.0 Mass Average Particle Size of μm 0.37 0.25 0.25 0.25 0.25 Rubber Component Unit ontent of Unsaturated Nitrile mass % 25.0 20.0 20.0 20.0 20.0 Monomer in Graft Vinyl-based Copolymer B-1 8.5 5.0 5.0 5.0 B-2 B-3 B-4 5.0 B-5 15.0 15.0 B-6 10.0 16.0 5.0 5.0 30.0 B-7 10.0 Methacrylic-based Copolymer M-1 60.0 50.0 M-2 M-3 60.0 M-4 60.0 M-5 50.0 Coloring Agent X-1 0.5 0.5 0.5 0.5 0.5 Acetone Insoluble Fraction (A) mass % 15.0 25.5 15.0 15.0 15.0 Acetone Soluble Fraction (B) mass % 85.0 74.5 85.0 85.0 85.0 Ratio of Methacrylate Monomer mass % 57.9 55.0 54.4 68.5 37.0 (in Acetone Soluble Fraction) Ratio of Maleimide-based mass % 7.2 6.0 0.0 0.0 12.5 Monomer Unit in 100 mass % of Thermoplastic Resin Composition Vicat Softening Point ° C. 119 114 119 101 125 Charpy Impact J/m2 8 12 8 8 8 Brightness (L*) — 6.6 6.7 6.1 5.7 6.7 Appearance Properties/Silver — ◯ ◯ X ◯ ◯ streaks Appearance Properties/White Haze — X X X ◯ ◯ Mass decrease ratio % 0.7 0.7 3.4 0.6 0.7 Pencil Hardness — F B F F B

(67) The description given so far reveals that a thermoplastic resin composition of the present invention provides an injection molded product that exhibits jet-blackness, scratch resistance, heat resistance and impact resistance and has stable and beautiful appearance free from silver streaks and white haze.

(68) This application is based upon the prior Japanese patent application (Japanese Patent Application No. 2013-233402) filed on Nov. 11, 2013 with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

(69) Since automotive interior parts of the present invention exhibits jet-blackness, scratch resistance and heat resistance, has stable and beautiful appearance free from silver streaks and white haze, and is excellent in impact resistance, it does not require coating, decoration or the like, and is excellent in surface appearances, and therefore, is economically and environmentally useful.