Polycarbonate resin composition and molded article thereof

Abstract

To provide a polycarbonate resin composition which simultaneously achieves both characteristics of rigidity and proof stress, and moldability and fluidity at a higher level, and is excellent in dimensional stability, and to provide a molded article thereof.SOLUTION: The polycarbonate resin composition contains a polycarbonate resin (A), a styrene-based resin (B), a flat cross-section glass fiber (C), and a glass flake (D). The average thickness of the glass flakes (D) is less than 0.45 μ m, the content of the styrene-based resin (B) is 25 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the total content of the polycarbonate resin (A) and the styrene-based resin (B), and the total content of the glass fibers (C) having an elliptical cross section and the glass flakes (D) is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the total content of the polycarbonate resin (A), the styrene-based resin (B), the glass fibers (C) having an elliptical cross section, and the glass flakes (D). The molded article is obtained from the polycarbonate resin composition.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 has traditionally been known for its excellent transparency, impact resistance, and heat resistance. The molded products obtained have excellent dimensional stability, making them suitable for use in electrical and electronic equipment parts, office automation equipment parts, etc. It is used in a wide range of fields, including automobiles, machinery parts, and vehicle parts.

[0003] Furthermore, polymer alloys made from polycarbonate resin and styrene-based resin are materials that utilize the excellent properties of polycarbonate resin as described above while also improving flexibility, lightness, and flowability, and are used in a wide range of applications, including vehicle interior and exterior parts, various housing components, and more.

[0004] Glass-based fillers are often blended into polycarbonate resins as reinforcing agents to improve their rigidity and dimensional stability. However, in recent years, there has been an extremely strong demand for improved appearance of molded articles in the various component applications mentioned above. Therefore, resin compositions in which the rigidity and dimensional stability have been increased by blending glass-based fillers are strongly required to have better fluidity and moldability in order to improve their appearance.

[0005] Regarding resin compositions in which a glass-based filler is blended into a polymer alloy of polycarbonate resin / styrene-based resin, Patent Document 1 proposes a polycarbonate resin composition blended with glass flakes having an average thickness of 0.45 to 1 μm and flat cross-section glass fibers having a specific flatness, as a composition having a linear expansion coefficient at the same level as metals and excellent impact resistance and strength. Patent Document 1 describes that the average thickness of the glass flakes is particularly preferably 0.6 to 0.8 μm, and that if the average thickness is below the lower limit of the above range, the glass flakes will be extremely prone to breakage, and their rigidity and impact resistance will decrease, which is undesirable. In the examples of Patent Document 1, glass flakes having an average thickness of 0.7 μm are specifically used. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-127405 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional resin compositions containing polycarbonate resins and glass-based fillers have improved rigidity and dimensional stability, but have the problem of reduced moldability (fluidity), resulting in poor appearance of molded products. Furthermore, resin compositions containing glass-based fillers have the drawback of failing to achieve isotropic dimensional stability because the orientation of the glass-based filler causes anisotropy in molding shrinkage.

[0008] In order to improve the moldability and flowability of a polymer alloy made of a polycarbonate resin and a styrene-based resin, it is conceivable to reduce the viscosity of the resin itself, but in this case, the rigidity and yield strength will decrease. That is, the rigidity and yield strength of a resin composition are in a trade-off relationship with the moldability and flowability, and the challenge is to achieve a good balance between the two.

[0009] The polycarbonate resin composition of Patent Document 1 is said to have a linear expansion coefficient at the same level as metals and to have excellent impact resistance and strength, but it is not necessarily sufficient in terms of achieving a high level of balance between rigidity and yield strength and fluidity and molded appearance. That is, as shown in Comparative Examples 1 and 2 below, when glass flakes with an average thickness of 0.7 μm are used, sufficient fluidity cannot be obtained to obtain an excellent molded appearance, and the appearance of the resulting molded article is inferior.

[0010] In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a polycarbonate resin composition which can simultaneously achieve higher levels of both rigidity and yield strength, and moldability and flowability, and which also has excellent dimensional stability, i.e., reduced anisotropy in dimensional accuracy, and a molded article thereof. [Means for solving the problem]

[0011] As a result of extensive research into achieving the above-mentioned object, the inventors have discovered that by blending a styrene-based resin, flat cross-section glass fibers, and glass flakes with an average thickness of less than 0.45 μm in a polycarbonate resin in specific proportions, it is possible to simultaneously achieve higher levels of both rigidity and dimensional accuracy, as well as moldability and flowability, and furthermore, it is possible to improve dimensional stability and reduce the anisotropy of dimensional accuracy, thereby completing the present invention. That is, the present invention is summarized as follows.

[0012] [1] A polycarbonate resin composition containing a polycarbonate resin (A), a styrene-based resin (B), a flat cross-section glass fiber (C), and glass flakes (D), The average thickness of the glass flakes (D) is less than 0.45 μm; the content of the styrene-based resin (B) is 25 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the total content of the polycarbonate resin (A) and the styrene-based resin (B); A polycarbonate resin composition in which the total content of the flat cross section glass fiber (C) and the glass flake (D) is 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total content of the polycarbonate resin (A), the styrene-based resin (B), the flat cross section glass fiber (C), and the glass flake (D).

[0013] [2] The polycarbonate resin composition according to [1], wherein the spiral flow length of the polycarbonate resin composition measured under the following condition (1) is 190 mm or more, and the molding shrinkage of the polycarbonate resin composition measured by the following method (2) is 0.25% or less. (1) Measurement conditions for spiral flow length Flow path thickness: 1mm Resin temperature: 300℃ Injection pressure: 150MPa Mold temperature: 80℃ Screw rotation speed: 100 rpm Injection speed: 50mm / s Back pressure: 10MPa Injection time: 10sec Cooling time: 15sec Suckback: 2mm Minimum cushioning: 6mm (2) Measurement method for molding shrinkage After 2mm thick, 100mm square injection molded test pieces are conditioned for 24 hours or more at a room temperature of 23°C and a humidity of 50%RH, the dimensions in the MD and TD directions are measured, and the molding shrinkage rate (unit: %) is calculated based on the dimensions of the injection molding mold.

[0014] [3] The polycarbonate resin composition according to [1] or [2], wherein the viscosity average molecular weight of the polycarbonate resin (A) is 16,000 to 50,000. [4] The melt volume rate (220 ° C, load 10 kg) of the styrene-based resin (B) is 60 cm 3 The polycarbonate resin composition according to any one of [1] to [3], wherein the elongation rate is 1000 kJ / 10 min or more. [5] The linear expansion coefficient in both the mechanical and transverse directions is 1.8×10, as measured according to ISO 11359-2. -5 / K~3.8×10 -5 / K, and the ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction is in the range of 0.8 to 1.1. [6] The polycarbonate resin composition according to any one of [1] to [5], wherein the styrene-based resin (B) is an acrylonitrile-styrene-based copolymer. [7] The polycarbonate resin composition according to any one of [1] to [6], wherein the average value of the flatness (long diameter / short diameter of fiber cross section) of the flat cross section glass fibers (C) is greater than 1.5 and is 8 or less. [8] The polycarbonate resin composition according to any one of [1] to [7], wherein the average minor axis of the fiber cross section of the flat cross section glass fibers (C) is 3 to 20 μm. [9] The polycarbonate resin composition according to any one of [1] to [8], wherein the mass ratio of the flat cross section glass fibers (C) to the glass flakes (D) (flat cross section glass fibers (C) / glass flakes (D)) is in the range of 0.2 to 4.0.

[0015]

[10] A molded article obtained from the polycarbonate resin composition according to any one of [1] to [9].

[11] The molded product according to

[10] , which is a molded product selected from the group consisting of housing parts and lens barrels of cameras, telescopes, microscopes, projection exposure devices, or optical measuring devices; housing parts and mechanical parts of smartphone cameras, in-vehicle cameras, drive recorders, surveillance cameras, or small cameras mounted on drones; housings and mechanical parts of car collision prevention sensors, rear monitor sensors, vehicle speed sensors, temperature sensors, or security sensors; frame members and outer panel members of automobiles, motorcycles, bicycles, or wheelchairs; panel members and mechanical parts of home televisions, personal computer displays, in-vehicle monitors, smartphones, or head-mounted displays; and housings and mechanical parts of barcode readers or scanners. [Effects of the Invention]

[0016] The present invention can provide a polycarbonate resin composition that can simultaneously achieve higher levels of both rigidity and yield strength, and moldability and flowability, and that has excellent flowability, resulting in a molded article with a good appearance and excellent dimensional stability, with particularly reduced anisotropy in dimensional accuracy, as well as a molded article produced using the polycarbonate resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below. Although the present invention may be based on exemplary embodiments and specific examples, it is to be understood that the present invention is not limited to such embodiments. It is not to be construed as being limited to the embodiments or specific examples. In this specification, unless otherwise specified, "~" indicates the numerical values ​​before and after it. are used in the sense of including the lower and upper limits.

[0018] [overview] The polycarbonate resin composition of the present invention is a polycarbonate resin composition containing polycarbonate resin (A), styrene-based resin (B), flat cross section glass fiber (C), and glass flakes (D), characterized in that the average thickness of the glass flakes (D) is less than 0.45 μm, the content of the styrene-based resin (B) is 25 parts by mass or more and 70 parts by mass or less per 100 parts by mass of the total content of the polycarbonate resin (A) and the styrene-based resin (B), and the total content of the flat cross section glass fiber (C) and the glass flakes (D) is 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total content of the polycarbonate resin (A), the styrene-based resin (B), the flat cross section glass fiber (C), and the glass flakes (D).

[0019] [mechanism] In the polycarbonate resin composition of the present invention, by using flat cross section glass fiber (C) in combination with glass flake (D) as a glass-based filler, it is possible to obtain a polycarbonate resin composition that is excellent in strength and low anisotropy of dimensional accuracy and has a linear expansion coefficient at the same level as that of metals such as aluminum and magnesium metal. In particular, by using extremely thin glass flake (D) with an average thickness of less than 0.45 μm, it is possible to increase the number of glass flakes per unit mass of the amount of glass flake (D) blended into the polycarbonate resin composition, which thereby further improves dimensional stability, reduces dimensional accuracy and its anisotropy, and increases mechanical strength such as rigidity. In addition, since the polycarbonate resin composition contains an appropriate amount of styrene-based resin (B), which is effective in improving fluidity, and the glass flakes (D) are extremely thin, the fluidity of the polycarbonate resin composition is improved, and the formation of a skin layer when filling a mold during molding is promoted, so that the flat cross-section glass fibers (C) and glass flakes (D) blended in the resin composition are embedded inside the molded article, improving the appearance of the resulting molded article.

[0020] [Polycarbonate resin (A)] The polycarbonate resin composition of the present invention contains a polycarbonate resin (A). There is no limitation on the type of polycarbonate resin (A) used in the polycarbonate resin composition of the present invention, and one type may be used alone, or two or more types may be used in any combination and in any ratio. Polycarbonate resin is a polymer with a basic structure having a carbonate bond represented by the general formula -(-OXOC(=O)-)-. In this formula, X is a hydrocarbon group, but X containing a heteroatom or hetero bond may also be used to impart various properties.

[0021] As the polycarbonate resin (A), an aromatic polycarbonate resin in which X in the above general formula is an aromatic hydrocarbon group is particularly preferred. An aromatic polycarbonate resin refers to a polycarbonate resin in which each carbon atom directly bonded to a carbonate bond is an aromatic carbon group. Among various polycarbonate resins, aromatic polycarbonate resins are superior in terms of heat resistance, mechanical properties, electrical properties, etc.

[0022] There are no specific limitations on the type of polycarbonate resin, such as an aromatic polycarbonate resin. Examples include polycarbonate polymers, such as an aromatic polycarbonate polymer obtained by reacting a dihydroxy compound with a carbonate precursor. In this case, a polyhydroxy compound or the like may be reacted in addition to the dihydroxy compound and carbonate precursor. Alternatively, a method of reacting carbon dioxide as a carbonate precursor with a cyclic ether may be used. Polycarbonate polymers, such as an aromatic polycarbonate polymer, may be linear or branched. Furthermore, polycarbonate polymers, such as an aromatic polycarbonate polymer, may be homopolymers composed of one type of repeating unit, or copolymers having two or more types of repeating units. Various copolymerization forms, such as random copolymers and block copolymers, may be selected for the copolymer. Typically, such polycarbonate polymers, such as an aromatic polycarbonate polymer, are thermoplastic resins.

[0023] <Raw material for polycarbonate resin> Among the monomers that serve as raw materials for polycarbonate resins, examples of aromatic dihydroxy compounds include the following.

[0024] dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (i.e., resorcinol), and 1,4-dihydroxybenzene; dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl; dihydroxynaphthalenes such as 2,2'-dihydroxy-1,1'-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene;

[0025] dihydroxydiaryl ethers such as 2,2'-dihydroxydiphenyl ether, 3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 1,4-bis(3-hydroxyphenoxy)benzene, and 1,3-bis(4-hydroxyphenoxy)benzene;

[0026] 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-methoxy-4-hydroxyphenyl)propane, 1,1-bis(3-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-cyclohexyl-4-hydroxyphenyl)propane, α,α'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)cyclohexylmethane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)(4-propenylphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)-1-naphthylethane, 1,1-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)hexane, 1,1-bis(4-hydroxyphenyl)octane, 2,2-bis(4-hydroxyphenyl)octane, 4,4-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxyphenyl)nonane, 1,10-bis(4-hydroxyphenyl)decane, 1,1-bis(4-hydroxyphenyl)dodecane, Bis(hydroxyaryl)alkanes such as;

[0027] 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,4-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,4-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-propyl-5-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3-phenylcyclohexane, 1,1-bis(4-hydroxyphenyl)-4-phenylcyclohexane, Bis(hydroxyaryl)cycloalkanes such as;

[0028] Cardo structure-containing bisphenols such as 9,9-bis(4-hydroxyphenyl)fluorene and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene; dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; Dihydroxydiarylsulfones such as 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone, etc.

[0029] Of these, bis(hydroxyaryl)alkanes are preferred, and bis(4-hydroxyphenyl)alkanes are particularly preferred, with 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) being particularly preferred from the standpoint of impact resistance and heat resistance. The aromatic dihydroxy compounds may be used alone or in any combination of two or more in any ratio.

[0030] Among the monomers that serve as raw materials for aliphatic polycarbonate resins, examples of aliphatic dihydroxy compounds include the following:

[0031] alkanediols such as ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 2-methyl-2-propylpropane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, and decane-1,10-diol;

[0032] cycloalkanediols such as cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, 1,4-cyclohexanedimethanol, 4-(2-hydroxyethyl)cyclohexanol, and 2,2,4,4-tetramethyl-cyclobutane-1,3-diol;

[0033] glycols such as ethylene glycol, 2,2'-oxydiethanol (i.e., diethylene glycol), triethylene glycol, propylene glycol, and spiroglycol;

[0034] aralkyldiols such as 1,2-benzenedimethanol, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 1,4-benzenediethanol, 1,3-bis(2-hydroxyethoxy)benzene, 1,4-bis(2-hydroxyethoxy)benzene, 2,3-bis(hydroxymethyl)naphthalene, 1,6-bis(hydroxyethoxy)naphthalene, 4,4'-biphenyldimethanol, 4,4'-biphenyldiethanol, 1,4-bis(2-hydroxyethoxy)biphenyl, bisphenol A bis(2-hydroxyethyl) ether, and bisphenol S bis(2-hydroxyethyl) ether;

[0035] Cyclic ethers such as 1,2-epoxyethane (i.e., ethylene oxide), 1,2-epoxypropane (i.e., propylene oxide), 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,4-epoxycyclohexane, 1-methyl-1,2-epoxycyclohexane, 2,3-epoxynorbornane, 1,3-epoxypropane, etc.

[0036] The aliphatic dihydroxy compounds may be used alone or in any combination of two or more in any ratio.

[0037] Among the monomers that serve as raw materials for polycarbonate resins, examples of carbonate precursors include carbonyl halides, carbonate esters, etc. The carbonate precursors may be used alone or in any combination and ratio of two or more.

[0038] Specific examples of carbonyl halides include phosgene; haloformates such as bischloroformates of dihydroxy compounds and monochloroformates of dihydroxy compounds; and the like. Specific examples of carbonate esters include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; biscarbonates of dihydroxy compounds, monocarbonates of dihydroxy compounds, and carbonates of dihydroxy compounds such as cyclic carbonates.

[0039] <Method for producing polycarbonate resin (A)> The method for producing the polycarbonate resin (A) is not particularly limited, and any method can be used. Examples include interfacial polymerization, melt transesterification, pyridine method, ring-opening polymerization of a cyclic carbonate compound, and solid-phase transesterification of a prepolymer. Particularly preferred methods among these methods will be specifically described below.

[0040] ≪Interfacial polymerization method≫ First, the production of polycarbonate resin by interfacial polymerization will be described. In interfacial polymerization, a dihydroxy compound and a carbonate precursor (preferably phosgene) are reacted in the presence of an organic solvent inert to the reaction and an aqueous alkaline solution, usually at a pH of 9 or higher, and then interfacial polymerization is carried out in the presence of a polymerization catalyst to obtain a polycarbonate resin. If necessary, a molecular weight modifier (terminal terminator) may be present in the reaction system, and an antioxidant may be present to prevent oxidation of the dihydroxy compound. The dihydroxy compound and carbonate precursor are as described above. Among the carbonate precursors, it is preferable to use phosgene, and the method using phosgene is particularly called the phosgene method.

[0041] Examples of organic solvents inert to the reaction include chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, monochlorobenzene, and dichlorobenzene; aromatic hydrocarbons such as benzene, toluene, and xylene; etc. One type of organic solvent may be used, or two or more types may be used in any combination and ratio.

[0042] Examples of the alkaline compound contained in the alkaline aqueous solution include alkali metal compounds and alkaline earth metal compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium bicarbonate, with sodium hydroxide and potassium hydroxide being preferred. The alkaline compounds may be used alone or in any combination and ratio of two or more. There is no limitation on the concentration of the alkali compound in the alkaline aqueous solution, but it is usually used at 5 to 10% by mass in order to control the pH of the alkaline aqueous solution in the reaction to 10 to 12. Furthermore, for example, when blowing in phosgene, in order to control the pH of the aqueous phase to 10 to 12, preferably 10 to 11, it is preferable that the molar ratio of the bisphenol compound to the alkali compound is usually 1:1.9 or more, particularly 1:2.0 or more, and usually 1:3.2 or less, particularly 1:2.5 or less.

[0043] Examples of the polymerization catalyst include aliphatic tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, and trihexylamine; alicyclic tertiary amines such as N,N'-dimethylcyclohexylamine and N,N'-diethylcyclohexylamine; aromatic tertiary amines such as N,N'-dimethylaniline and N,N'-diethylaniline; quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride, and triethylbenzylammonium chloride; pyridine; guanidine salts; etc. One type of polymerization catalyst may be used, or two or more types may be used in any combination and ratio.

[0044] Examples of molecular weight modifiers include aromatic phenols having a monovalent phenolic hydroxyl group; aliphatic alcohols such as methanol and butanol; mercaptans; and phthalimides, among which aromatic phenols are preferred. Specific examples of such aromatic phenols include alkyl-substituted phenols such as m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, p-tert-butylphenol, and p-long-chain alkyl-substituted phenols; vinyl-containing phenols such as isopropanylphenol; epoxy-containing phenols; and carboxyl-containing phenols such as 2-methyl-6-hydroxyphenylacetic acid. One type of molecular weight modifier may be used, or two or more types may be used in any combination and ratio. The amount of the molecular weight modifier used is usually 0.5 mol or more, preferably 1 mol or more, and usually 50 mol or less, preferably 30 mol or less, per 100 mol of the dihydroxy compound. By using the molecular weight modifier in this range, the thermal stability and hydrolysis resistance of the resulting polycarbonate resin can be improved.

[0045] During the reaction, the order in which the reaction substrate, reaction solvent, catalyst, additives, etc. are mixed may be any order as long as the desired polycarbonate resin is obtained, and any appropriate order may be set. For example, when phosgene is used as the carbonate precursor, the molecular weight modifier may be mixed at any time between the reaction of the dihydroxy compound with phosgene (phosgenation) and the start of the polymerization reaction. The reaction temperature is usually 0 to 40° C., and the reaction time is usually several minutes (for example, 10 minutes) to several hours (for example, 6 hours).

[0046] <Melt transesterification method> Next, a method for producing a polycarbonate resin by a melt transesterification method will be described. In the melt transesterification method, for example, a transesterification reaction is carried out between a carbonic acid diester and a dihydroxy compound.

[0047] The dihydroxy compound is as described above. On the other hand, examples of carbonate diesters include dialkyl carbonate compounds such as dimethyl carbonate, diethyl carbonate, and di-tert-butyl carbonate; diphenyl carbonate; and substituted diphenyl carbonates such as ditolyl carbonate. Among these, diphenyl carbonate and substituted diphenyl carbonates are preferred, with diphenyl carbonate being particularly preferred. Note that one type of carbonate diester may be used, or two or more types may be used in any combination and ratio.

[0048] The ratio of the dihydroxy compound to the carbonic acid diester may be any ratio as long as the desired polycarbonate resin can be obtained, but it is preferable to use an equimolar amount or more of the carbonic acid diester per mole of the dihydroxy compound, and more preferably 1.01 moles or more. The upper limit of this molar ratio is usually 1.30 moles or less. By adjusting the molar ratio within this range, the terminal hydroxyl group concentration of the resulting polycarbonate resin can be adjusted to a suitable range.

[0049] In polycarbonate resins, the terminal hydroxyl group concentration tends to have a significant effect on thermal stability, hydrolysis stability, color tone, etc. Therefore, the terminal hydroxyl group concentration may be adjusted as needed by any known method. In the transesterification reaction, a polycarbonate resin with an adjusted terminal hydroxyl group concentration can usually be obtained by adjusting the mixing ratio of the carbonic acid diester and the dihydroxy compound, the degree of reduced pressure during the transesterification reaction, etc. This operation can also adjust the molecular weight of the resulting polycarbonate resin.

[0050] When the concentration of terminal hydroxyl groups is adjusted by adjusting the mixing ratio of the carbonic acid diester and the dihydroxy compound, the mixing ratio is as described above. A more proactive adjustment method is to add a terminal terminator during the reaction. Examples of the terminal terminator include monohydric phenols, monocarboxylic acids, and carbonic acid diesters. The terminal terminator may be used alone or in any combination and ratio of two or more.

[0051] When producing a polycarbonate resin by the melt transesterification method, a transesterification catalyst is usually used. Any transesterification catalyst can be used. Among them, it is preferable to use, for example, an alkali metal compound and / or an alkaline earth metal compound. Furthermore, a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound may be used in combination as an auxiliary. Note that the transesterification catalyst may be used alone or in any combination and ratio of two or more types.

[0052] In the melt transesterification method, the reaction temperature is usually 100 to 320°C. The pressure during the reaction is usually reduced to 2 mmHg or less. Specifically, the melt polycondensation reaction may be carried out under the above conditions while removing by-products such as hydroxy compounds. The melt polycondensation reaction can be carried out by either a batch method or a continuous method. When carried out by a batch method, the order in which the reaction substrate, reaction solvent, catalyst, additives, etc. are mixed can be any order as long as the desired polycarbonate resin is obtained, and an appropriate order may be set as desired. However, in consideration of the stability of the polycarbonate resin, etc., it is preferable to carry out the melt polycondensation reaction by a continuous method.

[0053] In the melt transesterification method, a catalyst deactivator may be used as needed. As the catalyst deactivator, any compound that neutralizes the transesterification catalyst can be used. Examples thereof include sulfur-containing acidic compounds and their derivatives. The catalyst deactivator may be used alone or in any combination and ratio of two or more. The amount of the catalyst deactivator used is usually 0.5 equivalents or more, preferably 1 equivalent or more, and usually 10 equivalents or less, preferably 5 equivalents or less, relative to the alkali metal or alkaline earth metal contained in the transesterification catalyst, and is usually 1 ppm or more, and usually 100 ppm or less, preferably 20 ppm or less, relative to the polycarbonate resin.

[0054] <Structural viscosity index N of polycarbonate resin (A)> The polycarbonate resin (A) preferably contains at least a certain proportion of polycarbonate resins having a structural viscosity index N within a predetermined range. The structural viscosity index N is an index used to evaluate the flow characteristics of a melt, as detailed in the publication "Rheology for Chemists" (Kagaku Dojin, 1982, pp. 15-16). The melting characteristics of polycarbonate resins can usually be expressed by the formula γ = a·σN, where γ is the shear rate, a is a constant, σ is stress, and N is the structural viscosity index.

[0055] In the above formula, when N = 1, Newtonian fluidity is indicated, and the larger the value of N, the greater the non-Newtonian fluidity. In other words, the flow characteristics of a melt are evaluated based on the magnitude of the structural viscosity index N. In general, polycarbonate resins with a large structural viscosity index N tend to have high melt viscosity in the low shear region. Therefore, when a polycarbonate resin with a large structural viscosity index N is mixed with another polycarbonate resin, dripping during combustion of the resulting molded article can be suppressed, improving flame retardancy. However, in order to maintain the moldability of the resulting polycarbonate resin composition within a good range, it is preferable that the structural viscosity index N of this polycarbonate resin is not excessively large.

[0056] Therefore, it is preferable that the polycarbonate resin (A) contains a certain proportion or more of polycarbonate resin having a structural viscosity index N of usually 1.2 or more, preferably 1.25 or more, more preferably 1.28 or more, and usually 1.8 or less, preferably 1.7 or less. Such a high structural viscosity index N means that the polycarbonate resin has a branched structure, and by containing a polycarbonate resin with such a high structural viscosity index N, dripping during combustion of the resulting molded article can be suppressed, improving flame retardancy.

[0057] The structural viscosity index N can also be expressed by the following equation, Logηa = [(1-N) / N] × Logγ + C, derived from the above equation, as described in, for example, JP 2005-232442 A. In the equation, N is the structural viscosity index, γ is the shear rate, C is a constant, and ηa is the apparent viscosity. As can be seen from this equation, the N value can also be evaluated from γ and ηa in the low shear region where the viscosity behavior differs significantly. For example, the N value can be determined from ηa at γ = 12.16 sec-1 and γ = 24.32 sec-1.

[0058] As described in, for example, Japanese Patent Laid-Open Nos. 8-259687 and 8-245782, polycarbonate resins having a structural viscosity index N of 1.2 or more can be obtained by selecting catalyst conditions or production conditions when reacting a dihydroxy compound with a carbonate diester by a melting method (ester interchange method), without adding a branching agent, to obtain polycarbonate resins with a high structural viscosity index and excellent hydrolysis stability.

[0059] Polycarbonate resins having a structural viscosity index N of 1.2 or more can also be produced by a method using a branching agent when produced by a phosgene method or a melt method (ester interchange method) according to a conventional method. Specific examples of branching agents include polyhydroxy compounds such as phloroglucin, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 2,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-3, and 1,3,5-tris(4-hydroxyphenyl)ethane, as well as 3,3-bis(4-hydroxyaryl)oxindole (=isatin bisphenol), 5-chloroisatin bisphenol, 5,7-dichloroisatin bisphenol, and 5-bromoisatin bisphenol. The amount used is in the range of 0.01 to 10 mol %, particularly preferably 0.1 to 3 mol %, based on the dihydroxy compound.

[0060] In the polycarbonate resin composition of the present invention, the polycarbonate resin (A) preferably contains a polycarbonate resin having a structural viscosity index N falling within the specified range (hereinafter, this polycarbonate resin may be referred to as a "specified N polycarbonate resin") in an amount of typically 20% by mass or more, preferably 50% by mass or more, and more preferably 60% by mass or more of the polycarbonate resin (A). By using a specified N polycarbonate resin in this manner, torque does not increase more than necessary during extrusion, and therefore productivity is less likely to decrease. In other words, both moldability and productivity can be significantly improved. There is no upper limit to the content of the predetermined N polycarbonate resin in the polycarbonate resin (A), and it is usually 100% by mass or less, but it may be 90% by mass or less, or even 85% by mass or less. The specified N polycarbonate resin may be used alone or in any combination of two or more in any ratio. In addition to the above-mentioned specified N polycarbonate resin, the polycarbonate resin (A) may contain a polycarbonate resin whose structural viscosity index N is outside the above-mentioned specified range. There is no limitation on the type of polycarbonate resin, but linear polycarbonate resins are particularly preferred. Combining a specified N polycarbonate resin with a linear polycarbonate resin offers the advantage of easily balancing the flame retardancy (anti-drip property) and moldability (fluidity) of the resulting polycarbonate resin composition. From this perspective, the polycarbonate resin (A) may be composed of a specified N polycarbonate resin and a linear polycarbonate resin. The structural viscosity index N of this linear polycarbonate resin is usually about 1 to 1.15.

[0061] <Viscosity average molecular weight of polycarbonate resin (A)> The molecular weight of the polycarbonate resin (A) used in the present invention is preferably a viscosity-average molecular weight (Mv) of 16,000 to 50,000. If the viscosity-average molecular weight is less than 16,000, the mechanical strength is insufficient, and if the viscosity-average molecular weight exceeds 50,000, the flowability and moldability are poor. The viscosity-average molecular weight is preferably 18,000 or more, more preferably 19,000 or more, even more preferably 20,000 or more, particularly preferably 21,000 or more, and especially preferably 22,000 or more, while it is preferably 45,000 or less, more preferably 40,000 or less, even more preferably 36,000 or less, and especially preferably 33,000 or less. Methods for adjusting the molecular weight within these ranges include known methods such as controlling the amount of the molecular weight regulator described above.

[0062] In this specification, the viscosity average molecular weight (Mv) of a polycarbonate resin is determined by measuring the intrinsic viscosity [η] (unit: dl / g) at a temperature of 20°C using methylene chloride as a solvent with an Ubbelohde viscometer, and then calculating the viscosity average molecular weight (Mv) using the Schnell viscosity formula, i.e., η = 1.23 × 10 -4 Mv 0.83 The intrinsic viscosity [η] is the value calculated from the following formula after measuring the specific viscosity [ηsp] at each solution concentration [C] (g / dl).

[0063]

number

[0064] <Terminal hydroxyl group concentration of polycarbonate resin (A)> The terminal hydroxyl group concentration of the polycarbonate resin (A) is optional and may be appropriately selected and determined, but is typically 1,000 ppm by mass or less, preferably 800 ppm by mass or less, and more preferably 600 ppm by mass or less. This allows the residence heat stability and color tone of the polycarbonate resin composition of the present invention to be further improved. The lower limit is typically 10 ppm by mass or more, preferably 30 ppm by mass or more, and more preferably 40 ppm by mass or more, particularly for polycarbonate resin (A) produced by a melt transesterification method. This allows the molecular weight to be suppressed and the mechanical properties of the polycarbonate resin composition of the present invention to be further improved. When two or more polycarbonate resins having different terminal hydrogen group concentrations are mixed and used, the terminal hydroxyl group concentration is the actual value measured using the mixed polycarbonate resin by the method described below. The terminal hydroxyl group concentration is expressed in ppm by mass as the mass of the terminal hydroxyl groups relative to the mass of the polycarbonate resin. The terminal hydroxyl group concentration can be measured by colorimetric determination using the titanium tetrachloride / acetic acid method (the method described in Macromol. Chem. 88 215 (1965)).

[0065] <Form of polycarbonate resin (A)> The polycarbonate resin (A) is not limited to an embodiment containing only one type of polycarbonate resin, and two or more types of polycarbonate resins differing in monomer composition, molecular weight, terminal hydroxyl group concentration, etc. may be mixed and used.

[0066] Furthermore, for example, polycarbonate resin may be constituted as a copolymer mainly composed of polycarbonate resin, such as a copolymer with an oligomer or polymer having a siloxane structure for the purpose of further enhancing flame retardancy and impact resistance; a copolymer with a monomer, oligomer, or polymer having a phosphorus atom for the purpose of further improving thermal oxidation stability and flame retardancy; a copolymer with a monomer, oligomer, or polymer having a dihydroxyanthraquinone structure for the purpose of improving thermal oxidation stability; a copolymer with an oligomer or polymer having an olefin structure such as polystyrene for improving optical properties; or a copolymer with a polyester resin oligomer or polymer for the purpose of improving chemical resistance.

[0067] Furthermore, in order to improve the appearance and fluidity of molded articles, the polycarbonate resin (A) may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1,500 or more, preferably 2,000 or more, and usually 9,500 or less, preferably 9,000 or less. In this case, the polycarbonate oligomer contained in the polycarbonate resin (A) is preferably 30 mass % or less of the polycarbonate resin (A) (including the polycarbonate oligomer).

[0068] Furthermore, the polycarbonate resin (A) may be not only a virgin raw material but also a polycarbonate resin regenerated from used products (so-called material-recycled polycarbonate resin). Examples of the used products include optical recording media such as optical disks; light guide plates; transparent vehicle components such as automobile window glass, automobile headlamp lenses, and windshields; containers such as water bottles; eyeglass lenses; and building components such as soundproof walls, glass windows, and corrugated sheets. Also usable are crushed products obtained from non-conforming products, sprues, runners, etc., and pellets obtained by melting these.

[0069] When using such recycled polycarbonate resin, it is preferable to use one that contains as little foreign matter as possible, such as metal powder or coloring components, mixed in during the recycling process, so as not to impair the quality of the resulting molded product. For example, it is preferable that the number of foreign matter particles greater than 0.3 mm in size per 100 g of pellets is zero, more preferably greater than 0.2 mm but not greater than 0.3 mm, and particularly preferably greater than 0.1 mm but not greater than 0.2 mm, and not greater than 50. The recycled polycarbonate resin may account for a portion of the polycarbonate resin (A) contained in the polycarbonate resin composition of the present invention, for example, 80 mass % or less, and preferably 50 mass % or less. This is because recycled polycarbonate resins are likely to have been subjected to degradation such as thermal degradation and aging degradation, and therefore, if such polycarbonate resins are used in an amount greater than the above range, the color and mechanical properties may be deteriorated.

[0070] Commercially available recycled polycarbonate resins include "PC 2010A" manufactured by Ausell, "PC-116X" manufactured by Hongyu, and "MJ-311A" manufactured by MJ Material.

[0071] [Styrene-based resin (B)] The polycarbonate resin composition of the present invention contains a styrene-based resin (B). The type of styrene resin (B) is not particularly limited, and examples thereof include polystyrene, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butylene-styrene copolymer (ABS resin), acrylonitrile-styrene-acrylate copolymer (ASA resin), and methyl methacrylate-styrene copolymer (MS resin). From the viewpoint of fluidity, acrylonitrile-styrene copolymer (AS resin) is preferred. These may also be copolymerized with other copolymerizable monomers.

[0072] Examples of the styrene-based monomer constituting the styrene-based resin (B) include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred.

[0073] The content of units derived from acrylonitrile monomers in the acrylonitrile-styrene copolymer is preferably 5 to 50 mass%, more preferably 8 to 45 mass%, and the content of units derived from styrene monomers (hereinafter referred to as "styrene units") is preferably 50 to 95 mass%, more preferably 55 to 92 mass%.

[0074] In the acrylonitrile-styrene copolymer, examples of copolymerizable monomers other than the styrene monomer and acrylonitrile include (meth)acrylic acid ester monomers, maleimide monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide, and α,β-unsaturated carboxylic acids and anhydrides thereof such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid. Among these, (meth)acrylic acid ester monomers are preferred. Examples of (meth)acrylic acid ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate, with methyl methacrylate being particularly preferred. The term "(meth)acrylate" includes both methacrylate and acrylate, and the term "(meth)acrylic acid ester" includes both methacrylic acid ester and acrylic acid ester.

[0075] The method for producing the styrene-based resin (B) is not limited, and known methods can be used, such as bulk polymerization, emulsion polymerization, solution polymerization, and suspension polymerization.

[0076] The melt volume rate (MVR) of styrene resin (B) is 60cm, measured at 220°C under a load of 10 kg in accordance with JIS K7210A method. 3 / 10 minutes or more, e.g. 60-100cm 3 / 10min, and preferably in the range of 60 to 90cm 3 / 10 min is more preferable. The melt volume rate of the styrene resin (B) is 60 cm 3 If the viscosity is 100 cm / min or more, an excellent fluidity imparting effect can be obtained, and the appearance of the obtained molded product can be made even better. 3 If the heating time is 10 min or less, the above moldability can be ensured without significantly impairing the heat resistance of the resin composition.

[0077] The mass average molecular weight (Mw) of the styrene-based resin (B) is preferably in the range of 60,000 to 220,000, and more preferably 80,000 to 200,000. If the mass average molecular weight of the styrene-based resin (B) is 60,000 or more, the resin composition can have sufficient strength, but if it is 220,000 or more, the number of polymer entanglements increases, resulting in a high melt viscosity that is not practical. In the present invention, the mass average molecular weight (Mw) of the styrene-based resin (B) is a value calculated as polystyrene by GPC (gel permeation chromatography).

[0078] [Flat cross-section glass fiber (C)] The polycarbonate resin composition of the present invention contains flat cross section glass fibers (C). By using the flat cross section glass fibers (C) in combination with glass flakes (D) described below, it is possible to obtain a polycarbonate resin composition that is excellent in strength and low anisotropy of dimensional accuracy and has a linear expansion coefficient at the same level as that of metals such as aluminum and magnesium metal.

[0079] The flat cross section glass fiber (C) used in the present invention has a ratio of major axis (width) to minor axis (thickness) (major axis / minor axis (width / thickness), hereinafter referred to as "flatness") in a cross section (hereinafter simply referred to as "fiber cross section") perpendicular to the fiber length direction of the glass fiber, which ratio is preferably greater than 1.5 on average, more preferably 1.6 or more, even more preferably 1.8 or more, particularly preferably 2 or more, and preferably 8 or less, more preferably 7 or less, even more preferably 6 or less, particularly preferably 5 or less. If the flatness of the flat cross section glass fiber (C) is greater than 1.5, the dimensional anisotropy of the resin composition can be desirably reduced, and if it is 8 or less, it can be used without impairing the appearance of a molded article made from the resin composition.

[0080] The average major axis (width) of the fiber cross section of the flat cross section glass fiber (C) is preferably 10 to 50 μm, more preferably 12 to 40 μm, even more preferably 15 to 35 μm, and particularly preferably 18 to 30 μm. The average minor axis (thickness) of the fiber cross section of the flat cross section glass fiber (C) is preferably 3 to 20 μm, more preferably 4 to 15 μm, and even more preferably 5 to 12 μm. When the average value of the major axis and minor axis of the flat cross section glass fiber (C) is not less than the above lower limit, it contributes to the dimensional accuracy and rigidity-imparting effect of the resin composition, and when it is not more than the above upper limit, the fluidity of the resin composition can be kept within an appropriate range, and a good appearance can be obtained.

[0081] The number average fiber length of the flat cross section glass fibers (C) is preferably 0.5 to 20 mm, more preferably 1 to 15 mm, and even more preferably 2 to 10 mm. If the number average fiber length is equal to or greater than the lower limit, the material exhibits desirable rigidity and mechanical strength, and if it is equal to or less than the upper limit, the handleability during kneading processing is good. The ratio of the average fiber length to the average fiber diameter (aspect ratio) of the flat cross section glass fibers (C) is preferably 2 to 120, more preferably 2.5 to 70, and even more preferably 3 to 50. If the aspect ratio is less than 2, the mechanical strength tends to decrease, and conversely, if it exceeds 120, warpage and anisotropy increase, and the appearance of the molded article tends to deteriorate significantly.

[0082] The major axis, minor axis, fiber length, and fiber diameter (the fiber diameter corresponds to the major axis) of the flat cross section glass fiber (C) are values ​​measured by scanning electron microscope (SEM) observation, and these average values ​​are obtained by averaging the individual measurement values ​​of 3,000 to 10,000 pieces.

[0083] The glass composition of the flat cross section glass fiber (C) may be any glass composition commonly used in thermoplastic resins, including A-glass, E-glass, and alkali-resistant glass compositions containing zirconia components. Among these, the glass composition of the flat cross section glass fiber (C) used in the present invention is preferably alkali-free glass (E-glass) in order to improve the thermal stability of the polycarbonate resin composition.

[0084] The flat cross section glass fiber (C) used in the present invention can be surface treated with a silane coupling agent such as aminosilane or epoxysilane in order to improve adhesion to the polycarbonate resin.

[0085] The flat cross section glass fiber (C) is also preferably used as chopped strands obtained by bundling a large number of these fibers and cutting them to a predetermined length, and in this case, it is preferable to blend a sizing agent into the flat cross section glass fiber. By blending the sizing agent, good mechanical properties can be obtained in addition to the advantage of improving the production stability of the polycarbonate resin composition. The sizing agent is not particularly limited, but examples thereof include urethane-based, epoxy-based, and acrylic-based sizing agents.

[0086] Such flat cross section glass fibers (C) are commercially available as products such as "CSG 3PA830S" (flatness: 4.0) manufactured by Nitto Boseki Co., Ltd., "ECS 03 T-187-FGF" (flatness: 4.0) manufactured by Nippon Electric Glass Co., Ltd., and "ECS307AT-3-M4" manufactured by CPIC.

[0087] Glass Flakes The polycarbonate resin composition of the present invention contains glass flakes (D) having an average thickness of less than 0.45 μm. The glass flakes (D) used in the present invention have an average thickness of less than 0.45 μm, which is extremely thin compared to the thickness of ordinary glass flakes, which is about 5 μm. The average thickness of the glass flakes (D) is particularly preferably 0.3 to 0.4 μm. If the average thickness is 0.45 μm or more, the aforementioned effects of the present invention achieved by using ultrathin glass flakes (D) cannot be obtained. Furthermore, if the average thickness is below the lower limit of the above range, the glass flakes become extremely susceptible to cracking, and there is a risk of reduced rigidity and impact resistance.

[0088] Here, the average thickness of the glass flakes is a value measured by the following method. That is, the thickness of 100 or more glass flakes is measured using a scanning electron microscope (SEM) and the measured values ​​are averaged. In this case, the glass flakes may be observed individually with the scanning electron microscope, or the glass flakes may be filled into a resin and molded, then broken, and the fracture surface may be observed and measured.

[0089] The average particle size (length) of the glass flakes (D) is preferably 5 to 1000 μm, more preferably 20 to 700 μm, and even more preferably 50 to 200 μm. The average particle size here is the major axis of the glass flakes, and is calculated as the median diameter D50 of the weight-average distribution.

[0090] The glass composition of the glass flakes (D) is not particularly limited, and various glass compositions such as A-glass, C-glass, and E-glass can be appropriately selected and used.

[0091] The glass flakes (D) are preferably surface-treated with a known surface treatment agent, such as a silane coupling agent, methylhydrogensiloxane, titanate coupling agent, or aluminate coupling agent, from the viewpoint of improving mechanical strength. Furthermore, the glass flakes (D) are preferably granulated or bundled with a binder such as an acrylic resin, a urethane resin, an epoxy resin, or an unsaturated polyester resin, from the viewpoint of handling. However, the above-mentioned average particle size range and thickness range of the glass flakes (D) do not apply to the granules or bundles obtained by such granulation or bundling.

[0092] As the glass flakes (D) used in the present invention and having an average thickness of less than 0.45 μm, "MEC140FY-D01" (average thickness: 0.35 μm) manufactured by Nippon Sheet Glass Co., Ltd. is commercially available.

[0093] [Content of each component in polycarbonate resin composition] The content of the styrene resin (B) in the polycarbonate resin composition of the present invention is 25 to 70 parts by mass per 100 parts by mass of the total content of the polycarbonate resin (A) and the styrene resin (B). If the content of the styrene resin (B) is less than 25 parts by mass, the melt viscosity of the resin will be high and moldability will be poor, while if it exceeds 70 parts by mass, heat resistance will decrease and weld strength will also decrease. The content of the styrene resin (B) is preferably 27 parts by mass or more, more preferably 28 parts by mass or more, and preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, particularly preferably 50 parts by mass or less, and particularly preferably 40 parts by mass or less.

[0094] The total content of the flat cross section glass fiber (C) and the glass flake (D) in the polycarbonate resin composition of the present invention is 10 to 50 parts by mass, preferably 15 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, particularly preferably more than 30 parts by mass, and preferably 45 parts by mass or less, per 100 parts by mass of the total content of the polycarbonate resin (A), the styrene-based resin (B), the flat cross section glass fiber (C), and the glass flake (D). If the total content of the flat cross section glass fibers (C) and the glass flakes (D) is less than the lower limit, the effects of adding these to improve dimensional accuracy, low anisotropy, and reduced linear expansion coefficient will be insufficient. On the other hand, if the total content exceeds the upper limit, the flowability will decrease, and the moldability and the appearance of the resulting molded product will be inferior.

[0095] In addition, from the viewpoint of achieving a good balance between the effects of low anisotropy and imparting rigidity by using the flat cross section glass fiber (C) and the effects of reducing the linear expansion coefficient and imparting a good appearance by using the glass flakes (D), the content of the flat cross section glass fiber (C) is preferably 8 to 20 parts by mass, particularly 10 to 15 parts by mass, and the content of the glass flakes (D) is preferably 15 to 30 parts by mass, particularly 20 to 25 parts by mass, per 100 parts by mass of the total content of the polycarbonate resin (A) and the styrene-based resin (B), and the content ratio of the flat cross section glass fiber (C) to the glass flakes (D) (flat cross section glass fiber (C) / glass flakes (D)) is preferably in the range of 0.2 to 4.0, particularly 0.5 to 2.0.

[0096] The total content of the polycarbonate resin (A), the styrene-based resin (B), the flat cross section glass fiber (C), and the glass flakes (D) in the polycarbonate resin composition of the present invention is preferably 98% by mass or more, from the viewpoint of fully obtaining the respective effects of containing these components.

[0097] [Other additives] The polycarbonate resin composition of the present invention may further contain various additives within the range that does not impair the effects of the present invention, such as stabilizers, antioxidants, release agents, dyes and pigments, colorants, fluorescent brighteners, flame retardants, anti-dripping agents, antistatic agents, anti-fogging agents, lubricants, anti-blocking agents, flow improvers, plasticizers, dispersants, antibacterial agents, and flame retardants.

[0098] <Phosphorus-based stabilizer> The polycarbonate resin composition of the present invention preferably contains a phosphorus-based stabilizer. Any known phosphorus-based stabilizer can be used. Specific examples include phosphorus oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; metal acid pyrophosphates such as sodium acid pyrophosphate, potassium acid pyrophosphate, and calcium acid pyrophosphate; phosphates of Group 1 or Group 2B metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; organic phosphate compounds, organic phosphonite compounds, organic phosphite compounds, and zinc salts of organic phosphate ester compounds. Of these, organic phosphite compounds and zinc salts of organic phosphate ester compounds are particularly preferred.

[0099] Examples of organic phosphite compounds include triphenyl phosphite, tris(mononylphenyl)phosphite, tris(mononyl / dinonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecylmonophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite. Commercially available organic phosphite compounds include Adeka STAB 1178, Adeka STAB 2112, and Adeka STAB HP-10 manufactured by ADEKA Corporation, JP-351, JP-360, and JP-3CP manufactured by Johoku Chemical Industry Co., Ltd., and Irgafos 168 manufactured by BASF.

[0100] Preferred examples of zinc salts of organic phosphate ester compounds include zinc salts of stearyl acid phosphate, such as bis(distearyl acid phosphate) zinc salt and monostearyl acid phosphate zinc salt. Commercially available zinc salts of these organic phosphate ester compounds include "JP-518Zn" manufactured by Johoku Chemical Industry Co., Ltd.

[0101] The phosphorus-based stabilizer may be contained either as one type or as two or more types in any combination and ratio.

[0102] When the polycarbonate resin composition of the present invention contains a phosphorus-based stabilizer, the content thereof is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and usually 1 part by mass or less, preferably 0.7 parts by mass or less, more preferably 0.5 parts by mass or less, per 100 parts by mass of the polycarbonate resin (A) and the styrene-based resin (B) combined. If the content of the phosphorus-based stabilizer is at least the lower limit of the above range, a sufficient thermal stabilization effect can be obtained. If the content of the phosphorus-based stabilizer exceeds the upper limit of the above range, the effect may plateau and become uneconomical.

[0103] <Phenol-based stabilizer> The polycarbonate resin composition of the present invention also preferably contains a phenolic stabilizer. Examples of the phenolic stabilizer include hindered phenolic antioxidants. Specific examples thereof include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate, 3,3',3'',5,5',5''-hexa-tert-butyl-a,a',a''-(mesitylene-2,4,6 -triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, and the like.

[0104] Among these, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are preferred. Specific examples of commercially available phenolic antioxidants include "Irganox 1010" and "Irganox 1076" manufactured by BASF, and "Adekastab AO-50" and "Adekastab AO-60" manufactured by ADEKA.

[0105] The phenolic stabilizer may be contained in one kind or in any combination and ratio of two or more kinds.

[0106] When the polycarbonate resin composition of the present invention contains a phenolic stabilizer, the content thereof is usually 0.001 part by mass or more, preferably 0.01 part by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the styrene-based resin (B). If the content of the phenolic stabilizer is equal to or greater than the lower limit of the above range, the effect as a phenolic stabilizer can be sufficiently obtained. If the content of the phenolic stabilizer exceeds the upper limit of the above range, the effect may plateau and the composition may become uneconomical.

[0107] <Release agent> The polycarbonate resin composition of the present invention preferably contains a mold release agent (lubricant). Examples of the mold release agent include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, and polysiloxane-based silicone oils.

[0108] Examples of aliphatic carboxylic acids include saturated or unsaturated aliphatic mono-, di-, or tri-carboxylic acids. Aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are mono- or di-carboxylic acids having 6 to 36 carbon atoms, with saturated aliphatic mono-carboxylic acids having 6 to 36 carbon atoms being more preferred. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetralinic acid, montanic acid, adipic acid, and azelaic acid.

[0109] The aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol can be, for example, the same as the aliphatic carboxylic acid described above. On the other hand, the alcohol can be, for example, a saturated or unsaturated monohydric or polyhydric alcohol. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, a monohydric or polyhydric saturated alcohol having 30 or less carbon atoms is preferred, and an aliphatic saturated monohydric alcohol or an aliphatic saturated polyhydric alcohol having 30 or less carbon atoms is more preferred. Here, the term "aliphatic" is used to include alicyclic compounds.

[0110] Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, and dipentaerythritol.

[0111] The ester may contain an aliphatic carboxylic acid and / or an alcohol as an impurity. The ester may be a single substance or a mixture of multiple compounds. The aliphatic carboxylic acid and the alcohol that combine to form an ester may each be used alone or in any combination and ratio of two or more.

[0112] Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture containing myricyl palmitate as a main component), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, and pentaerythritol tetrastearate.

[0113] Examples of aliphatic hydrocarbons having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microcrystalline wax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. Aliphatic hydrocarbons also include alicyclic hydrocarbons. These hydrocarbons may also be partially oxidized.

[0114] Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferred, and paraffin wax and polyethylene wax are more preferred. The number average molecular weight of the aliphatic hydrocarbon is preferably 5,000 or less. The aliphatic hydrocarbon may be a single substance, but a mixture of substances with various constituent components and molecular weights can also be used as long as the main component is within the above range.

[0115] Examples of polysiloxane-based silicone oils include dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil, and fluorinated alkyl silicone.

[0116] The above-mentioned release agents may be contained either alone or in any combination and ratio of two or more.

[0117] When the polycarbonate resin composition of the present invention contains a mold release agent, the content thereof is usually 0.001 part by mass or more, preferably 0.01 part by mass or more, and usually 2 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the styrene-based resin (B). When the content of the mold release agent is equal to or greater than the lower limit of the above range, the effect of mold releasability can be sufficiently obtained. When the content of the mold release agent exceeds the upper limit of the above range, there is a possibility that the hydrolysis resistance will decrease and mold contamination during injection molding will occur.

[0118] <Dyes and pigments> Examples of the dyes and pigments include inorganic pigments, organic pigments, and organic dyes. Examples of inorganic pigments include sulfide pigments such as carbon black, cadmium red, and cadmium yellow; silicate pigments such as ultramarine; oxide pigments such as titanium oxide, zinc white, red iron oxide, chromium oxide, iron black, titanium yellow, zinc-iron brown, titanium-cobalt green, cobalt green, cobalt blue, copper-chromium black, and copper-iron black; chromate pigments such as yellow lead and molybdate orange; and ferrocyanide pigments such as iron blue.

[0119] Examples of organic pigments and organic dyes include phthalocyanine-based dyes and pigments such as copper phthalocyanine blue and copper phthalocyanine green; azo-based dyes and pigments such as nickel azo yellow; condensed polycyclic dyes and pigments such as thioindigo-based, perinone-based, perylene-based, quinacridone-based, dioxazine-based, isoindolinone-based, and quinophthalone-based; and quinoline-based, anthraquinone-based, heterocyclic, and methyl-based dyes and pigments.

[0120] Among these, carbon black, titanium oxide, cyanine-based, quinoline-based, anthraquinone-based, and phthalocyanine-based dyes and pigments are preferred from the viewpoint of thermal stability. The dye or pigment may be contained in one kind or in any combination and ratio of two or more kinds. Furthermore, the dye or pigment may be used in the form of a masterbatch with a polystyrene resin, a polycarbonate resin, or an acrylic resin, for the purposes of improving handling during extrusion and improving dispersibility in the resin composition.

[0121] When the polycarbonate resin composition of the present invention contains a dye or pigment, the content thereof is usually 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 2 parts by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the styrene-based resin (B). If the content of the dye or pigment is too high, the impact resistance may become insufficient.

[0122] [Other resins] The polycarbonate resin composition of the present invention may contain other resins in addition to the polycarbonate resin (A) and the styrene-based resin (B). Examples of other resins include thermoplastic polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate, and polybutylene terephthalate resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resin; polyimide resin; polyetherimide resin; polyphenylene ether resin; polyphenylene sulfide resin; and polysulfone resin. One type of other resin may be contained, or two or more types may be contained in any combination and ratio.

[0123] However, from the viewpoint of fully obtaining the effect of the polycarbonate resin composition of the present invention being a polymer alloy of polycarbonate resin (A) and styrene-based resin (B), when the polycarbonate resin composition of the present invention contains a resin other than polycarbonate resin (A) and styrene-based resin (B), the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of polycarbonate resin (A).

[0124] [Method for producing polycarbonate resin composition] The method for producing the polycarbonate resin composition of the present invention is not limited, and a wide variety of known methods for producing polycarbonate resin compositions can be used. For example, the polycarbonate resin (A), styrene-based resin (B), flat cross-section glass fiber (C), glass flake (D), and other components as needed may be premixed using a mixer such as a tumbler, Henschel mixer, super mixer, or ribbon blender, and then melt-kneaded using a mixer such as a Banbury mixer, roll, Brabender, single-screw kneading extruder, twin-screw kneading extruder, or kneader. Side-feeding of the flat cross-section glass fiber (C) and glass flake (D) is also preferred, if necessary. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C.

[0125] [Physical properties of polycarbonate resin composition] <Spiral flow length> The fluidity of a polycarbonate resin composition can be evaluated by its spiral flow length. The spiral flow length of the polycarbonate resin composition of the present invention, measured by the method described in the Examples section below, is preferably 190 mm or more, more preferably 200 mm or more, and even more preferably 210 mm or more. Having a spiral flow length equal to or greater than the above-mentioned lower limit allows for excellent fluidity, good moldability, and the production of molded articles with good appearance. The upper limit of the spiral flow length is usually 400 mm, since, from the viewpoint of maintaining mechanical strength and heat resistance, it is necessary to adjust the composition formulation within a range that does not cause polymer decomposition.

[0126] <Molding shrinkage rate> The mold shrinkage of the polycarbonate resin composition of the present invention, measured by the method described in the Examples section below, is preferably 0.25% or less, more preferably 0.2% or less, and even more preferably 0.18% or less. Having a mold shrinkage of not more than the upper limit mentioned above provides excellent dimensional accuracy. The smaller this mold shrinkage, the better.

[0127] <Linear expansion coefficient> The linear expansion coefficient of the polycarbonate resin composition of the present invention, measured by the method described in the Examples section below, is 1.8 × 10 in both the MD and TD directions, from the viewpoint of having a linear expansion coefficient at the same level as metals and controlling the dimensional accuracy of molded products to the same level as dissimilar materials (glass and metal materials). -5 / K~3.8×10 -5 / K, and is preferably in the range of 2.0 × 10 -5 / K~3.4×10 -5 / K, and more preferably in the range of 2.1 × 10 -5 / K~2.8×10 -5 It is more preferable that the range is / K.

[0128] <Anisotropy of dimensional accuracy> The ratio of the linear expansion coefficients in MD and TD (MD / TD) of the polycarbonate resin composition of the present invention, measured by the method described in the Examples section below, is preferably within a range of 0.8 to 1.1, and more preferably within a range of 0.9 to 1.0, from the viewpoint of low anisotropy in dimensional accuracy.

[0129] <Flexural modulus> The flexural modulus of the polycarbonate resin composition of the present invention, measured by the method described in the Examples section below, is preferably 7,500 MPa or more, more preferably 9,000 MPa or more, from the viewpoint of rigidity. The higher the flexural modulus, the better, and there is no particular upper limit, but it is usually 15,000 MPa or less.

[0130] [Method for molding polycarbonate resin composition] The polycarbonate resin composition of the present invention can be pelletized and molded into molded articles by various molding methods. Alternatively, the resin can be melt-kneaded in an extruder and directly molded into sheets, films, profile extrusion molded articles, blow molded articles, injection molded articles, etc., without going through pelletization.

[0131] Examples of molding methods include injection molding, ultra-high speed injection molding, injection compression molding, two-color molding, gas-assisted and other hollow molding methods, molding using an insulated mold, molding using a rapidly heated mold, foam molding (including supercritical fluids), insert molding, IMC (in-mold coating molding), extrusion molding, sheet molding, thermoforming, rotational molding, laminate molding, press molding, etc. Molding methods using a hot runner system can also be used.

[0132] There are no restrictions on the shape, pattern, color, size, etc. of the molded product, and these may be set arbitrarily depending on the application of the molded product.

[0133] [Molded products] The polycarbonate resin composition of the present invention is excellent in rigidity, dimensional stability, dimensional accuracy and its low anisotropy, moldability, flowability, and molded article appearance, and is therefore suitable for various molded articles that require toughness, strength, and appearance while being thin-walled. Specifically, the molded article of the present invention obtained by molding the polycarbonate resin composition of the present invention can be particularly suitably used as housing parts and lens barrels for cameras, telescopes, microscopes, projection exposure devices, and optical measuring devices; housing parts and mechanical parts for smartphone cameras, in-vehicle cameras, drive recorders, surveillance cameras, and small cameras mounted on drones; housings and mechanical parts for car collision prevention sensors, rear monitor sensors, vehicle speed sensors, temperature sensors, and security sensors; frame members and outer panel members for automobiles, motorcycles, bicycles, and wheelchairs; panel members and mechanical parts for home televisions, personal computer displays, in-vehicle monitors, smartphones, and head-mounted displays; and housings and mechanical parts for barcode readers and scanners. [Example]

[0134] The present invention will be explained in more detail below by showing examples, but the present invention should not be construed as being limited to the following examples.

[0135] [Materials used] The materials used in the examples and comparative examples are as shown in Tables 1 and 2 below.

[0136] [Table 1]

[0137] [Table 2]

[0138] [Examples 1 to 6, Comparative Examples 1 to 5] <Production of Polycarbonate Resin Composition> The materials listed in Tables 1 and 2 above were mixed in a tumbler for 20 minutes in the amounts (all parts by mass) listed in Tables 3 and 4 below, and then fed into a twin-screw extruder (TEX25αIII) equipped with one vent, manufactured by The Japan Steel Works, Ltd., and kneaded under conditions of a screw rotation speed of 200 rpm, a discharge rate of 20 kg / hour, and a barrel temperature of 290°C. The molten resin composition extruded in the form of strands was quenched in a water tank and pelletized using a pelletizer to obtain pellets of a polycarbonate resin composition.

[0139] <Molding of test piece I> The obtained pellets were dried at 120°C for at least 5 hours and then injection molded in an injection molding machine (Sumitomo Heavy Industries, Ltd., "SE100EV-A-SHR") under conditions of a cylinder temperature of 280°C, a mold temperature of 80°C, and a molding cycle of 40 seconds to produce 2 mm thick, 100 mm square test pieces I.

[0140] <Molding of test piece II> The obtained pellets were dried at 120°C for 5 hours and then molded into 4 mm thick ISO dumbbell test pieces II using an injection molding machine (NEX80 manufactured by Nissei Plastic Industrial Co., Ltd.) under the following conditions: cylinder temperature 300°C, mold temperature 100°C, injection speed 100 mm / s, and holding pressure 80 MPa.

[0141] [Measurement and evaluation methods] <Spiral flow length> The spiral flow length of the polycarbonate resin composition was measured under the following conditions: flow channel thickness 1 mm, resin temperature 300°C, injection pressure 150 MPa, mold temperature 80°C, screw rotation 100 rpm, injection speed 50 mm / s, back pressure 10 MPa, injection time 10 sec, cooling time 15 sec, suck back 2 mm, and minimum cushion amount 6 mm.

[0142] <Molding shrinkage rate> The 100 mm square test piece I obtained above was conditioned for 24 hours or more in an environment at room temperature of 23° C. and humidity of 50% RH. Then, using the obtained test piece, the dimensions in the MD (Machine Direction, also called the flow direction) and TD (Transverse Direction, also called the perpendicular direction) directions were measured, and the molding shrinkage rate (unit: %) was calculated based on the dimensions of the injection molding mold.

[0143] <Linear expansion coefficient> The center of the 100 mm square test piece I obtained above was cut into a size of 10 mm length x 10 mm width x 2 mm thickness in the MD / TD directions, and the test piece was used to measure the linear expansion coefficient based on ISO11359-2. The measuring device used was the Hitachi High-Tech Science "TMA7100." The length of the test piece was measured, and the temperature was raised from -40 to +80°C at a rate of 20°C / min. The linear expansion coefficient (unit: / K) was calculated from the slope of the change in dimensions relative to the change in temperature.

[0144] <Anisotropy of dimensional accuracy> The ratio of the linear expansion coefficients in the MD and TD calculated above (MD / TD) was calculated.

[0145] <Flexural modulus> The ISO dumbbell test piece II (thickness: 4 mm) obtained above was used to measure the flexural modulus (unit: MPa) in accordance with ISO178.

[0146] <Appearance> The surface appearance of the 100 mm square test piece I obtained above was observed and evaluated according to the following evaluation criteria. ◎: No floating of glass filler on the molding surface, very good ○: Slight floating of glass filler is observed △: The glass filler is noticeably lifted and whitened ×: The glass filler is noticeably lifted, and the product is not suitable for practical use.

[0147] The above evaluation results are shown in Tables 3 and 4.

[0148] [Table 3]

[0149] [Table 4]

[0150] From Table 2, it can be seen that the polycarbonate resin composition of the present invention is excellent in rigidity, dimensional accuracy, low anisotropy, moldability and flowability, and that due to its excellent flowability and moldability, molded articles with excellent appearance can be molded. In contrast, as shown in Table 3, in Comparative Examples 1 and 2 in which glass flakes with a large average thickness were used, the spiral flow length was short, resulting in poor appearance of the molded product. In addition, in Comparative Example 3, in which the content of the styrene-based resin (B) relative to the total of the polycarbonate resin (A) and the styrene-based resin (B) was low, the spiral flow length was very short, and as a result, the appearance of the molded product was very poor. In Comparative Example 4, in which the total content of the flat cross section glass fiber (C) and the glass flakes (D) was low, the molding shrinkage rate and the linear expansion coefficient were large, resulting in poor dimensional accuracy. Conversely, in Comparative Example 5, in which the total content of the flat cross section glass fiber (C) and the glass flakes (D) was too high, the spiral flow length was short, and the appearance of the resulting molded article was very poor. [Industrial Applicability]

[0151] INDUSTRIAL APPLICABILITY The polycarbonate resin composition of the present invention is suitable for various molded articles that require thin wall thickness, rigidity, and good appearance, and can be used in a wide range of fields such as interior and exterior parts of automobiles and the like, and housings for electric and electronic equipment and office automation equipment, and has extremely high industrial applicability.

Claims

1. A polycarbonate resin composition containing a polycarbonate resin (A), a styrene-based resin (B), a flat cross section glass fiber (C), and glass flakes (D), The average thickness of the glass flakes (D) is less than 0.45 μm; the content of the styrene-based resin (B) is 25 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the total content of the polycarbonate resin (A) and the styrene-based resin (B); A polycarbonate resin composition in which the total content of the flat cross section glass fiber (C) and the glass flake (D) is 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total content of the polycarbonate resin (A), the styrene-based resin (B), the flat cross section glass fiber (C), and the glass flake (D).

2. 2. The polycarbonate resin composition according to claim 1, wherein the spiral flow length of the polycarbonate resin composition measured under the following condition (1) is 190 mm or more, and the molding shrinkage of the polycarbonate resin composition measured by the following method (2) is 0.25% or less. (1) Measurement conditions for spiral flow length Flow path thickness: 1 mm Resin temperature: 300℃ Injection pressure: 150 MPa Mold temperature: 80°C Screw rotation speed: 100 rpm Injection speed: 50mm / s Back pressure: 10MPa Injection time: 10sec Cooling time: 15sec Suck back: 2mm Minimum cushioning: 6 mm (2) Method for measuring molding shrinkage An injection-molded test piece, 2 mm thick and 100 mm square, is conditioned for 24 hours or more at a room temperature of 23°C and a humidity of 50% RH, and then the dimensions in the MD and TD directions are measured, and the molding shrinkage (unit: %) is calculated based on the dimensions of the injection molding die.

3. 2. The polycarbonate resin composition according to claim 1, wherein the viscosity average molecular weight of the polycarbonate resin (A) is 16,000 to 50,000.

4. The melt volume rate (220°C, load 10 kg) of the styrene-based resin (B) is 60 cm ３ 2. The polycarbonate resin composition according to claim 1, wherein the melting point is 1000 rpm or more.

5. The linear expansion coefficient in the MD and TD directions measured based on ISO11359-2 is 1.8 x 10 －５ / K ~ 3.8 x 10 －５ / K, and the ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction is in the range of 0.8 to 1.

1.

6. 2. The polycarbonate resin composition according to claim 1, wherein the styrene-based resin (B) is an acrylonitrile-styrene-based copolymer.

7. 2. The polycarbonate resin composition according to claim 1, wherein the average flatness (long diameter / short diameter of fiber cross section) of the flat cross section glass fibers (C) is greater than 1.5 and less than or equal to 8.

8. 2. The polycarbonate resin composition according to claim 1, wherein the average minor axis of the fiber cross section of the flat cross section glass fiber (C) is 3 to 20 μm.

9. The polycarbonate resin composition according to claim 1, wherein the content mass ratio of the flat cross section glass fiber (C) to the glass flake (D) (flat cross section glass fiber (C) / glass flake (D)) is in the range of 0.2 to 4.

0.

10. A molded article obtained from the polycarbonate resin composition according to any one of claims 1 to 9.

11. The molded article according to claim 10, which is a molded article selected from the group consisting of housing parts and lens barrels of cameras, telescopes, microscopes, projection exposure devices, or optical measuring devices; housing parts and mechanical parts of smartphone cameras, in-vehicle cameras, drive recorders, surveillance cameras, or small cameras mounted on drones; housings and mechanical parts of car collision prevention sensors, rear monitor sensors, vehicle speed sensors, temperature sensors, or security sensors; frame members and outer panel members of automobiles, motorcycles, bicycles, or wheelchairs; panel members and mechanical parts of home televisions, personal computer displays, in-vehicle monitors, smartphones, or head-mounted displays; and housings and mechanical parts of barcode readers or scanners.

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