Polycarbonate resin composition and molded article thereof

Abstract

To provide a polycarbonate resin composition which is suppressed in fluidity change during molding, is excellent in residence heat stability, is suppressed in discoloration, and has high designability even when the resin component is only a polycarbonate resin, and to provide a molded article thereof.SOLUTION: A polycarbonate resin composition comprising, based on 100 parts by weight of an aromatic polycarbonate resin (A), 0.05 to 3 parts by weight of a metal oxide-coated plate-shaped filler (B) and 1 part by weight or less (for example, 0.001 part by weight or more and 1 part by weight or less) of an antioxidant (C).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Polycarbonate resin is a thermoplastic resin with excellent color development, impact resistance, heat resistance, and thermal stability, and these properties have led to its widespread use in fields such as electricity, electronics, ITE (information technology equipment), machinery, and automobiles. In recent years, there has been a demand for diverse designs, particularly in the housings of home appliances, electronic devices, and image display devices, as well as in automobile interiors, and the use of polycarbonate resin is expected to grow.

[0003] Patent Document 1 discloses a highly designable polycarbonate resin composition containing 100 parts by mass of polycarbonate resin (A), 0.1 to 5 parts by mass of metal oxide-coated plate-like filler (B), 0.01 to 1 part by mass of one or more phosphate stabilizers (C) selected from alkyl acid phosphate, alkenyl acid phosphate, and metal salts thereof, and 0.003 to 0.15 parts by mass of hydrogensiloxane (D). The metal oxide-coated plate-like filler used has a coating layer containing titanium oxide and tin oxide formed on a substrate.

[0004] Patent Document 2 discloses that a thermoplastic resin composition that can replace gold paint can be obtained by combining and blending a plate-like filler (B) having a coating layer containing titanium oxide, iron oxide, silicon oxide, and tin oxide formed on the substrate, and a plate-like filler (C) having a coating layer containing titanium oxide, silicon oxide, and tin oxide formed on the substrate, into an aromatic polycarbonate resin.

[0005] Furthermore, Patent Document 3 discloses that when the resin component is only polycarbonate resin, the resin has poor moist heat resistance and retention heat stability, and therefore a resin composition containing a combined system of polycarbonate resin and polyester resin or styrene-based thermoplastic resin, a metal pigment having a specific average particle size, aspect ratio, and iron concentration, and an organic phosphate ester compound can be used to produce a molded product with a metallic appearance and excellent moist heat resistance, and which also has excellent retention heat stability.

[0006] Patent Document 4 discloses that in a resin composition containing a combined system of a polycarbonate resin and a polyester resin or a styrene-based thermoplastic resin, by blending a metal pigment as a masterbatch, the metal pigment is less likely to break, and molded articles with excellent metallic appearance and moist heat resistance can be produced, and a polycarbonate resin composition with excellent retention heat stability can be obtained. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6593187 [Patent Document 2] Patent No. 6672987 [Patent Document 3] Patent No. 5634980 [Patent Document 4] Patent No. 5634981 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention relates to a highly designable polycarbonate resin composition that exhibits suppressed fluidity changes during molding and excellent retention heat stability even when the resin component is polycarbonate resin alone, and to a molded article made thereof. [Means for solving the problem]

[0009] The present invention relates to the following [1] and [2]. [1] A polycarbonate resin composition containing 100 parts by weight of an aromatic polycarbonate resin (A), 0.05 to 3 parts by weight of a metal oxide-coated plate-like filler (B), and 1 part by weight or less of an antioxidant (C). [2] A polycarbonate resin molded article containing the polycarbonate resin composition according to [1]. [Effects of the Invention]

[0010] The polycarbonate resin composition of the present invention exhibits the excellent effect of suppressing changes in flowability during molding and exhibiting excellent retention heat stability, thereby enabling the resulting molded article to have an even better appearance. DETAILED DESCRIPTION OF THE INVENTION

[0011] The polycarbonate resin composition of the present invention contains 100 parts by weight of aromatic polycarbonate resin (A), 0.05 to 3 parts by weight of metal oxide-coated plate-like filler (B), and 1 part by weight or less of antioxidant (C).

[0012] In an embodiment of the present invention, the "aromatic polycarbonate resin (A)" is a polycarbonate resin based on an aromatic compound, and is not particularly limited as long as it can produce the aromatic polycarbonate resin composition of the present invention. Examples of such aromatic polycarbonate resins include polymers obtained by the phosgene method, in which various dihydroxydiaryl compounds are reacted with phosgene, or the transesterification method, in which a dihydroxydiaryl compound is reacted with a carbonate ester such as diphenyl carbonate. A representative example includes a polycarbonate resin produced from 2,2-bis(4-hydroxyphenyl)propane (bisphenol A).

[0013] Examples of the dihydroxydiaryl compound include, in addition to bisphenol A, bis(hydroxyaryl)alkanes such as bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane; Examples of suitable hydroxyaryl compounds include bis(hydroxyaryl)cycloalkanes such as bis(4-hydroxyphenyl)cyclopentane and 1,1-bis(4-hydroxyphenyl)cyclohexane; dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone. These compounds may be used alone or in combination. Other compounds that may be used in combination include piperazine, dipiperidyl hydroquinone, resorcinol, and 4,4'-dihydroxydiphenyl.

[0014] Furthermore, the dihydroxydiaryl compound may be used in combination with, for example, the following trivalent or higher aromatic compounds.

[0015] Examples of the trivalent or higher aromatic compounds include phloroglucin, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene, 2,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane, and 2,2-bis-[4,4-(4,4'-dihydroxydiphenyl)-cyclohexyl]-propane.

[0016] The viscosity average molecular weight of the aromatic polycarbonate resin (A) is preferably 10,000 to 100,000, and more preferably 12,000 to 30,000. When producing such an aromatic polycarbonate resin (A), a molecular weight modifier, a catalyst, etc. may be used as needed. As such an aromatic polycarbonate resin, commercially available products may be used.

[0017] In an embodiment of the present invention, the "metal oxide-coated plate-like filler (B)" is a plate-like filler that serves as a base material and is coated with a metal oxide, and the brilliance, saturation, color tone, etc. can be changed depending on the type of metal oxide and the thickness of the coating layer.

[0018] Examples of materials that can be used to form the plate-like filler include mica, silica, alumina, and glass.

[0019] Examples of metal oxides that coat such flake-like fillers include titanium oxide, tin oxide, silicon oxide, iron oxide, etc. These may be used alone or in combination of two or more.

[0020] The metal oxide-coated plate-like filler may be prepared by coating a plate-like filler with a metal oxide according to a known method, or a commercially available product may be used. These may be used alone or in combination of two or more.

[0021] Examples of commercially available products include "Colorstream T10-01 Viola Fantasy," "Colorstream T10-02 Arctic Fire," "Colorstream T10-03 Tropic Sunrise," and "Colorstream T10-04 Lapis Sunlight," all manufactured by MERCK.

[0022] The average particle size of the metal oxide-coated plate-like filler is not particularly limited, and may be 1 to 500 μm, 3 to 300 μm, or 5 to 100 μm. In this specification, the average particle size refers to the volume median particle size (D ) at which the cumulative volume frequency calculated by volume fraction is 50% from the smallest particle size. 50 ) means

[0023] The average aspect ratio of the metal oxide-coated plate-like filler (major axis of filler / thickness of filler) is not particularly limited, and may be 10 or more, or may be 15-40.

[0024] The content of the metal oxide-coated plate-like filler (B) is 0.05 parts by weight or more, preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, and 3 parts by weight or less, preferably 2 parts by weight or less, per 100 parts by weight of the aromatic polycarbonate resin (A).

[0025] In an embodiment of the present invention, the "antioxidant (C)" preferably contains one or more antioxidants selected from phosphorus-based antioxidants and phenol-based antioxidants. In the present invention, it is presumed that the antioxidant sterically or environmentally inhibits the reaction of the aromatic polycarbonate resin with the metal oxide-coated flake filler, which would otherwise result in a lower molecular weight due to long residence time in the cylinder of the injection molding machine.

[0026] The phosphorus-based antioxidant is not particularly limited as long as it can produce the polycarbonate resin composition of the present invention, and examples thereof include phosphite ester compounds having the following structure:

[0027] [ka]

[0028] The phosphite ester compound preferably includes at least one compound selected from the group consisting of phosphite ester compounds represented by the following formula (1), phosphite ester compounds represented by the following formula (2), phosphite ester compounds represented by the following formula (3), and phosphite ester compounds represented by the following formula (4), and more preferably includes at least one compound selected from the group consisting of phosphite ester compounds represented by the following formula (2), phosphite ester compounds represented by the following formula (3), and phosphite ester compounds represented by the following formula (4).

[0029] Formula (1): [ka] (In the formula, R 1 represents an alkyl group having 1 to 20 carbon atoms, and a represents an integer of 0 to 3.

[0030] In the formula (1), R 1 is an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms.

[0031] Examples of the compound represented by formula (1) include triphenyl phosphite, tricresyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, trisnonylphenyl phosphite, etc. Among these, tris(2,4-di-t-butylphenyl) phosphite is preferred and is commercially available, for example, as Irgafos 168 manufactured by BASF ("Irgafos" is a registered trademark of BASF Societas Europea).

[0032] Formula (2): [ka] (In the formula, R 2 , R 3 , R 5 and R 6 R each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. 4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; X represents a single bond, a sulfur atom, or a group of the formula: -CHR 7 -(where R 7 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. A represents an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR 8 -(where R 8 represents a single bond or an alkylene group having 1 to 8 carbon atoms, and * represents a bond on the oxygen side. Either Y or Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

[0033] R in equation (2) 2 , R 3 , R 5 and R 6are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, a t-pentyl group, an i-octyl group, a t-octyl group, and a 2-ethylhexyl group. Examples of the cycloalkyl group having 5 to 8 carbon atoms include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the alkylcycloalkyl group having 6 to 12 carbon atoms include a 1-methylcyclopentyl group, a 1-methylcyclohexyl group, and a 1-methyl-4-i-propylcyclohexyl group. Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, an α-methylbenzyl group, and an α,α-dimethylbenzyl group.

[0034] R 2 , R 3 and R 5 are each independently preferably an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcycloalkyl group having 6 to 12 carbon atoms. 2 and R 5 are preferably each independently a t-alkyl group such as a t-butyl group, a t-pentyl group, or a t-octyl group, a cyclohexyl group, or a 1-methylcyclohexyl group. 3 is preferably an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, or a t-pentyl group, and more preferably a methyl group, a t-butyl group, or a t-pentyl group.

[0035] R 6is preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms, and more preferably a hydrogen atom, or an alkyl group having 1 to 5 carbon atoms such as a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, or t-pentyl group.

[0036] In equation (2), R 4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 Among them, R 4 is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom or a methyl group.

[0037] In formula (2), X represents a single bond, a sulfur atom, or a group represented by the formula: -CHR 7 -, where the formula is -CHR 7 -R in 7 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms and the cycloalkyl group having 5 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 Among these, X is preferably a single bond, a methylene group, or a methylene group substituted with a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, or the like, and more preferably a single bond.

[0038] In formula (2), A is an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR 8- represents a group represented by the formula: *-COR. Examples of the alkylene group having 1 to 8 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, and a 2,2-dimethyl-1,3-propylene group, and the like, with a propylene group being preferred. 8 -R in 8 represents a single bond or an alkylene group having 1 to 8 carbon atoms. 8 Examples of the alkylene group having 1 to 8 carbon atoms represented by R include the alkylene groups exemplified in the description of A. 8 is preferably a single bond or an ethylene group. 8 The * in - is the bond on the oxygen side, indicating that the carbonyl group is bonded to the oxygen atom of the phosphite group.

[0039] In formula (2), either Y or Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkoxy group having 1 to 8 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a t-butoxy group, and a pentyloxy group. Examples of the aralkyloxy group having 7 to 12 carbon atoms include a benzyloxy group, an α-methylbenzyloxy group, and an α,α-dimethylbenzyloxy group. Examples of the alkyl group having 1 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 Examples of the alkyl groups include those exemplified in the explanation of 1.

[0040] Examples of the compound represented by formula (2) include 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine, 6 -[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, and the like. Among these, when using a polycarbonate resin composition obtained in a field requiring high designability, 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine is suitable, and is commercially available, for example, as Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd. ("Sumilizer" is a registered trademark).

[0041] Formula (3): [ka] (In the formula, R 9 and R 10 each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and b and c each independently represent an integer of 0 to 3.

[0042] Examples of the compound represented by formula (3) include bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, etc. Bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is commercially available as "ADK STAB PEP-24G" manufactured by ADEKA Corporation, and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is commercially available as "ADK STAB PEP-36" manufactured by ADEKA Corporation.

[0043] Formula (4): [ka] (In the formula, R 11 ~R 18 R each independently represents an alkyl group or alkenyl group having 1 to 3 carbon atoms. 11 and R 12 , R 13 and R 14 , R 15 and R 16 , R 17 and R 18 may be bonded to each other to form a ring. 19 ~R 22 each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. d to g each independently represents an integer of 0 to 5. X 1 ~X 4 X each independently represents a single bond or a carbon atom. 1 ~X 4 is a single bond, R 11 ~R 22 Among these, the functional group connected to the single bond is excluded from general formula (4).

[0044] A specific example of the compound represented by formula (4) is bis(2,4-dicumylphenyl)pentaerythritol diphosphite, which is commercially available as "Doverphos (registered trademark) S-9228" manufactured by Dover Chemical Co. and "ADEKA STAB PEP-45" manufactured by ADEKA Corporation.

[0045] Furthermore, instead of or in addition to any of the compounds represented by the above formulas (1) to (4), a compound represented by the following formula (5) may be used.

[0046] Formula (5): [ka] (In the formula, R 23 ~R 26 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.

[0047] Specific examples of the compound represented by formula (5) include, for example, [1,1'-biphenyl]-4,4-diylbis[bis(2,4-di-t-butylphenoxy)phosphine], and the like, which are commercially available, for example, as "Irgafos P-EPQ" manufactured by BASF and "Sandstab P-EPQ" manufactured by Clariant Japan.

[0048] In the present invention, a phosphate ester compound represented by the following general formula (I) and / or phosphoric acid can be used as the phosphorus-based antioxidant. Formula (I): O=P(OH) n (OR) 3-n [In formula (I), R represents an alkyl group or an aryl group, and may be the same or different, and n represents an integer of 0 to 3.]

[0049] In the above general formula (I), R is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and more preferably an alkyl group having 2 to 25 carbon atoms. Furthermore, n is preferably 1 or 2.

[0050] Examples of the phosphate ester compound of formula (I) include mono- or di-stearyl acid phosphate, and a mixed stearyl phosphate ester (a mixture of about 50 mol% monostearyl phosphate and about 50 mol% distearyl phosphate ("AX-71" manufactured by ADEKA Corporation) is known.

[0051] Phosphoric acid is a non-volatile weak acid, and commercially available products can be used without any particular limitation. Examples include phosphoric acid manufactured by Nacalai Tesque, Inc. and phosphoric acid manufactured by Wako Pure Chemical Industries, Ltd.

[0052] From the viewpoint of suppressing the reaction between the aromatic polycarbonate resin and the metal oxide-coated plate-like filler, the phosphorus-based antioxidant preferably contains at least one selected from the group consisting of a phosphite ester compound having the following structure, a phosphate ester compound, and phosphoric acid.

[0053] [ka]

[0054] The phenol-based antioxidant includes a compound represented by the following formula (6).

[0055] Formula (6) [ka] (Wherein, R 27 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.

[0056] A commercially available compound represented by formula (6) is "ADEKA STAB AO-50" (n-octadecyl-3(3',5'-di-t-butyl-4-hydroxyphenyl)propionate) manufactured by ADEKA Corporation.

[0057] The amount of antioxidant (C) added is 1 part by weight or less, preferably 0.5 parts by weight or less, and more preferably 0.2 parts by weight or less, per 100 parts by weight of aromatic polycarbonate resin (A). There is no particular lower limit, but it is, for example, 0.001 parts by weight or more, preferably 0.01 parts by weight or more. When multiple antioxidants are used, the total content is expressed. An amount exceeding 1 part by weight is undesirable because it can lead to a deterioration in physical properties and insufficient thermal stability during retention during molding, which can cause discoloration of the aromatic polycarbonate resin (A) or poor color expression due to the metal oxide-coated flake filler (B).

[0058] In addition to the above-mentioned components, the polycarbonate resin composition of the present invention may contain heat stabilizers, other antioxidants, other pigments, colorants, release agents, softeners, flame retardants, UV absorbers, antistatic agents, impact modifiers, etc., within limits that do not impair the effects of the present invention. It is also possible to contain other polymeric materials and other resin compositions within limits that do not impair the effects of the present invention. The contents of these can be appropriately adjusted according to known techniques.

[0059] The polycarbonate resin composition of the present invention contains an aromatic polycarbonate resin (A), a metal oxide-coated platy filler (B), and an antioxidant (C). It can be prepared without any particular limitations, so long as the content of the metal oxide-coated platy filler (B) is 0.05 to 3 parts by weight and the content of the antioxidant (C) is 1 part by weight or less per 100 parts by weight of the aromatic polycarbonate resin (A). The aromatic polycarbonate resin (A), the metal oxide-coated platy filler (B), and the antioxidant (C) are mixed with other optional components in any known mixer, such as a tumbler or ribbon blender, and then melt-kneaded in a conventional single-screw or twin-screw extruder. The resulting melt-kneaded product may be in the form of pellets, which may be dried or cooled.

[0060] The shape and size of the pellets of the polycarbonate resin composition obtained as described above are not particularly limited, and may be any shape and size common to resin pellets. Examples of pellet shapes include elliptical cylinders and cylindrical shapes. The pellet size is preferably about 2 to 8 mm in length. In the case of an elliptical cylinder, the major axis of the cross-sectional ellipse is preferably about 2 to 8 mm and the minor axis is preferably about 1 to 4 mm. In the case of a cylindrical shape, the diameter of the cross-sectional circle is preferably about 1 to 6 mm. Each of the obtained pellets may be of this size, or all of the pellets forming a pellet aggregate may be of this size, or the average size of the pellet aggregate may be of this size, and there are no particular limitations.

[0061] The polycarbonate resin composition of the present invention contains the antioxidant (C) described above, which prevents the aromatic polycarbonate resin (A) from being reduced in molecular weight and prevents a decrease in fluidity during melting. The melt volume rate (MVR, cm) of the prepared pellets is compared with that of the aromatic polycarbonate resin. 3 / 10 minutes) is preferably less than 5, more preferably not more than 3. MVR can be measured in accordance with ISO 1133.

[0062] The polycarbonate resin composition of the present invention has excellent thermal stability, and therefore, for example, even if it remains in a cylinder during injection molding, it is possible to suppress a decrease in molecular weight and discoloration. When comparing the obtained molded article, for example, when it remains at 280°C for 10 minutes with when it does not remain, the decrease in molecular weight is preferably less than 500, more preferably less than 400. Furthermore, when measured with a spectrophotometer, ΔY is preferably less than 4.0, more preferably 3.5 or less.

[0063] The present invention also provides a molded article (also simply referred to as a polycarbonate resin molded article) obtainable by molding the polycarbonate resin composition. The polycarbonate resin molded article is not particularly limited as long as it contains the polycarbonate resin composition, and can be obtained, for example, by filling pellets of the polycarbonate resin composition into an injection molding machine and injecting them into a mold for molding.

[0064] The polycarbonate resin molded article of the present invention has excellent moldability of the polycarbonate resin composition and excellent distribution of the metal oxide-coated plate-like filler, and therefore has high designability. For example, it can be suitably used for housings of home appliances, electronic devices, and image display devices, and automobile interior parts. [Example]

[0065] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.

[0066] Examples 1 to 7 and Comparative Examples 1 to 2 The ingredients used are shown below. (A) Aromatic polycarbonate resin Polycarbonate resin synthesized from bisphenol A and carbonyl chloride Viscosity average molecular weight: 18,800, Sumika Polycarbonate's "SD Polyca (registered trademark) 200-20" (B) Metal oxide coated plate-like filler (b1) Merck Polarized Pearl Colorstream T10-04 Lapis Sunlight (b2) Merck Polarized Pearl Colorstream T10-03 Tropic Sunrise (C) Antioxidants (c1) Nacalai Tesque, phosphoric acid (H3PO4) (c2) Stearyl phosphate mixed ester (a mixture of approximately 50 mol% monostearyl phosphate and approximately 50 mol% distearyl phosphate; manufactured by ADEKA, Adeka STAB "AX-71")

[0067] These components were dry- and wet-mixed in a tumbler in the weight ratios shown in Table 1, and then melt-kneaded at 260°C using a twin-screw extruder (TEX30α, manufactured by The Japan Steel Works, Ltd.) to obtain pellets of a polycarbonate resin composition. The obtained pellets were subjected to the following various evaluations. The results are shown in Table 1.

[0068] Test Example 1 <Melt Volume Rate (MVR)> The melt volume rate (MVR) of the resulting pellets was measured using a Melt Flow Index Tester 120-SAS-1 (manufactured by Yasuda Seiki Seisakusho) under a 1.2 kg load at 300°C in accordance with ISO 1133. The MVR of the polycarbonate resin (PC) used as the raw material alone was also measured under the same conditions, and the value (hereinafter referred to as ΔMVR) was calculated by subtracting the MVR of the PC from the MVR of the resulting pellets. A ΔMVR value of less than 5 was considered pass (○), and a value of 5 or greater was considered fail (×).

[0069] Test Example 2 <Retention Heat Stability (Decrease in Molecular Weight)> The obtained pellets were dried at 120°C for at least 4 hours, and then flat test specimens (length 80 mm, width 50 mm, thickness 3 mm) were produced using an injection molding machine (FANUC, ROBOSHOT S2000i100B) at a molding temperature of 280°C under the following two conditions. Condition 1: No retention Condition 2: Retention (10 minutes in the cylinder)

[0070] Each of the flat test pieces obtained above was dissolved in methylene chloride to prepare a solution with a concentration of 0.38 wt %. The viscosity of the obtained solution was measured at 20°C using a Cannon-Fenske viscometer. The viscosity average molecular weight was calculated according to the following formula. [η]=1.23×10 -4 M 0.83 however, [η]: Intrinsic viscosity M: Viscosity average molecular weight

[0071] When the viscosity average molecular weight under condition 1 (no retention) is MW0 and the viscosity average molecular weight under condition 2 (retention) is MW1, MW0 of 23,000 or more was considered a pass (○), and MW less than 23,000 was considered a fail. Furthermore, the value obtained by subtracting MW1 from MW0 (hereinafter abbreviated as ΔMW) of less than 500 was considered a pass (○), and 500 or more was considered a fail (×).

[0072] Test Example 3 <Retention Heat Stability (Discoloration)> The molded article obtained in Test Example 2 was used to measure the change in YI (ΔYI) in accordance with ASTM D-1925 using a spectrophotometer (Murakami Color Research Laboratory, CMS-35SP). YI represents the degree of yellowness; the smaller the YI, the less yellowness and coloration. ΔYI was defined as the difference between the YI value of the flat test piece obtained under Condition 2 (with retention) and the YI value of the flat test piece obtained under Condition 1 (without retention). ΔYI values ​​of less than 4.0 were rated as good (◯), and values ​​of 4.0 or greater were rated as poor (×).

[0073] [Table 1]

[0074] The above results demonstrate that the polycarbonate resin composition of the present invention suppresses a decrease in fluidity and has excellent retention heat stability. Furthermore, Examples 2 and 5 demonstrate that even when different types of metal oxide-coated plate-like filler were used, no decrease in molecular weight due to retention in the cylinder was observed, and favorable results were achieved. Example 7 demonstrates that the combined use of different types of antioxidants effectively suppresses the reaction between the aromatic polycarbonate resin and the metal oxide-coated plate-like filler, maintaining the good color tone of the metal oxide-coated plate-like filler, and achieving excellent results. On the other hand, Comparative Examples 1 and 2, because they did not contain an antioxidant, did not suppress the reduction in molecular weight of the polyester resin, resulting in decreased fluidity and poor retention heat stability. [Industrial Applicability]

[0075] The polycarbonate resin composition of the present invention can be suitably used for various industrial applications such as daily necessities, home appliance parts, packaging materials for home appliance parts, and automobile parts.

Claims

1. A polycarbonate resin composition comprising 100 parts by weight of an aromatic polycarbonate resin (A), 0.05 to 3 parts by weight of a metal oxide-coated plate-like filler (B), and 1 part by weight or less of an antioxidant (C).

2. 2. The polycarbonate resin composition according to claim 1, wherein the antioxidant (C) is a phosphorus-based antioxidant and / or a phenol-based antioxidant.

3. 2. The polycarbonate resin composition according to claim 1, wherein the phosphorus-based antioxidant comprises at least one member selected from the group consisting of a phosphite compound having the following phosphite structure, a phosphate ester compound, and phosphoric acid: 【Chemistry 1】

4. 4. The polycarbonate resin composition according to claim 3, wherein the phosphorus-based antioxidant comprises at least one compound selected from the group consisting of phosphite ester compounds represented by the following formulas (1), (2), (3), (4), and (5): Formula (1): 【Chemistry 2】 [In the formula, R １ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a represents an integer of 0 to 3. Formula (2): 【Transformation 3】 [In the formula, R ２ , R ３ , R ５ and R ６ R each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. ４ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; X represents a single bond, a sulfur atom, or a group represented by the formula: -CHR ７ - (where R ７ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. A represents an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR ８ - (where R ８ represents a single bond or an alkylene group having 1 to 8 carbon atoms, and * represents a bond on the oxygen side. Either Y or Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.] Formula (3): 【Chemistry 4】 [In the formula, R ９ , R １０ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and b and c each independently represent an integer of 0 to 3. Formula (4): 【Transformation 5】 [In the formula, R １１ ~R １８ R each independently represents an alkyl group or alkenyl group having 1 to 3 carbon atoms. １１ and R １２ , R １３ and R １４ , R １５ and R １６ , R １７ and R １８ may be bonded to each other to form a ring. １９ ~R ２２ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. d to g each independently represent an integer of 0 to 5. X １ ~X ４ each independently represents a single bond or a carbon atom. １ ~X ４ is a single bond, R １１ ~R ２２ Among these, the functional group connected to the single bond is excluded from formula (4). Formula (5): 【Transformation 6】 (In the formula, R ２３ ~R ２６ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.

5. The polycarbonate resin composition according to claim 4, which satisfies at least one selected from the following: the phosphite ester compound represented by formula (1) contains tris(2,4-di-t-butylphenyl)phosphite; the phosphite compound represented by formula (2) contains 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine; the phosphite compound represented by formula (3) contains 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane; The phosphite compound represented by the formula (4) contains bis(2,4-dicumylphenyl)pentaerythritol diphosphite; and The phosphite compound represented by the formula (5) contains [1,1'-biphenyl]-4,4'-diylbis[bis(2,4-di-t-butylphenoxy)phosphine].

6. 4. The polycarbonate resin composition according to claim 3, wherein the phosphorus-based antioxidant comprises a phosphoric acid ester compound represented by the following formula (I): Formula (I): O=P(OH) ｎ (OR) ３－ｎ [In formula (I), R represents an alkyl group or an aryl group, and may be the same or different, and n represents an integer of 0 to 3.]

7. 4. The polycarbonate resin composition according to claim 3, wherein the phosphorus-based antioxidant comprises a phosphate ester compound represented by the following formula (I) and phosphoric acid: Formula (I): O=P(OH) ｎ (OR) ３－ｎ [In formula (I), R represents an alkyl group or an aryl group, and may be the same or different, and n represents an integer of 0 to 3.]

8. A polycarbonate resin molded article comprising the polycarbonate resin composition according to any one of claims 1 to 7.

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