Polycarbonate resin composition and molded article

Abstract

To provide a polycarbonate resin composition and a molded article which generate less squeak noise (abnormal sound), and are also excellent in self-tapping properties.SOLUTION: A polycarbonate resin composition contains 55-90 pts.mass of a polycarbonate resin (A), 10-45 pts.mass of a graft copolymer (B) containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2) and a diene-based rubbery polymer component (b3), and 1.5-5.5 pts.mass of an ethylene-(meth)acrylate copolymer (C) with respect to 100 pts.mass of the total of (A) and (B), wherein a ratio of a constitutional unit derived from the (meth)acrylate of the ethylene-(meth)acrylate copolymer (C) is more than 0 mass% and less than 20 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polycarbonate resin composition and a molded article, and more particularly to a polycarbonate resin composition and a molded article that generate little rattling noise (abnormal noise) and are excellent in self-tapping properties.

Background Art

[0002] A resin alloy obtained by blending an ABS resin with a polycarbonate resin is excellent in moldability, impact resistance, mechanical strength, and heat resistance, and is therefore suitably used as parts and members for electric and electronic devices such as vehicles, computers, notebook computers, various mobile terminals, printers, copiers, etc., and OA and information devices. In particular, in automobiles and the like, polycarbonate resin / ABS resin alloys have been widely used as interior materials for reasons such as ease of molding and weight reduction.

[0003] Products installed in automobiles, such as those represented by displays, console panels, dashboards, car navigation systems, etc., are manufactured by fitting and assembling resin molded parts for weight reduction purposes. For example, when they have a housing structure, usually, fitting portions for fitting are integrally formed at various locations on the upper and lower split molded members, and screws or the like are hardly used or used minimally, and the outer peripheral edges of the upper and lower molded members are faced and fitted to produce a housing molded product.

[0004] However, when such molded products are installed in a vehicle, the temperature in the automobile interior changes drastically from low to high temperatures, and the resin molded products are likely to be deformed due to shrinkage and expansion caused by thermal fluctuations. If even a slight deformation occurs in the fitting portion, rattling noise is likely to be generated due to vibrations during the running of the automobile. Rattling noise greatly impairs the comfort during driving, and especially in luxury cars, a higher level of interior quietness is required, so preventing the generation of rattling noise is an extremely important issue.

[0005] However, molded articles made of a polycarbonate resin / ABS resin alloy are likely to generate a squeaking sound (abnormal noise) when the molded articles come into dynamic contact with each other, such as during vibration. In order to reduce this squeaking sound, it has been proposed to use AES resin instead of ABS resin in the polycarbonate resin / ABS resin alloy (see Patent Document 1). However, when a product molded from an alloy in which AES resin is substituted for ABS resin is used for a long time in a high-temperature environment, a squeaking sound may easily occur.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In addition, in order to fit and screw the above-described molding members together, it is also necessary to have excellent self-tapping properties. An object of the present invention is to provide a polycarbonate resin composition and a molded article that generate little squeaking sound (abnormal noise), generate little squeaking sound (abnormal noise) even when used for a long time in a high-temperature environment as vehicle parts, etc., and have excellent self-tapping properties.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above problems, the present inventor has found that a polycarbonate resin composition containing a polycarbonate resin rich in polycarbonate resin and an alloy with ABS resin or the like and containing an ethylene-(meth)acrylate copolymer having a proportion of structural units derived from (meth)acrylate less than a specific amount in a specific amount generates little squeaking sound (abnormal noise) and has excellent self-tapping properties, and has thus completed the present invention. That is, the present invention relates to the following polycarbonate resin composition and molded article.

[0009] 1. A polycarbonate resin composition comprising 55 to 90 parts by mass of a polycarbonate resin (A) and 1.5 to 5.5 parts by mass of an ethylene-(meth)acrylate copolymer (C) based on 100 parts by mass in total of (A) and (B), wherein (B) is a graft copolymer containing 10 to 45 parts by mass of an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2), and a diene rubber polymer component (b3), and the proportion of the structural unit derived from the (meth)acrylate ester of the ethylene-(meth)acrylate copolymer (C) is more than 0% by mass and less than 20% by mass. 2. The polycarbonate resin composition according to 1 above, having a shear strength of 19 MPa or more based on JIS K7214. 3. A molded article comprising the polycarbonate resin composition according to 1 or 2 above. 4. The molded article according to 3 above, wherein the molded article is an automotive interior part.

Advantages of the Invention

[0010] The polycarbonate resin composition of the present invention generates less rattling noise (abnormal noise), and also generates less rattling noise (abnormal noise) even when used for a long time in a high-temperature environment as a vehicle part or the like, and is also excellent in self-tapping property. Therefore, the molded article formed from the polycarbonate resin composition of the present invention can be particularly preferably used, especially as an automotive interior part or the like.

Modes for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail with reference to embodiments and examples, etc., but the present invention is not limited to the following embodiments and examples, etc. In the present specification, "~" is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value.

[0012] The polycarbonate resin composition of the present invention contains 55 to 90 parts by mass of a polycarbonate resin (A) and 10 to 45 parts by mass of a graft copolymer (B) containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2), and a diene rubber polymer component (b3). With respect to a total of 100 parts by mass of (A) and (B), 1.5 to 5.5 parts by mass of an ethylene-(meth)acrylate copolymer (C) is contained, and the proportion of the structural unit derived from the (meth)acrylate of the ethylene-(meth)acrylate copolymer (C) is more than 0% by mass and less than 20% by mass.

[0013] [Polycarbonate resin (A)] The polycarbonate resin (A) contained in the polycarbonate resin composition of the present invention is not limited in its type, and only one type may be used, or two or more types may be used in combination at any combination and any ratio. The polycarbonate resin is a polymer having a basic structure with a carbonate bond represented by the general formula: -[-O-X-O-C(=O)-]-. In the above formula, X is generally a hydrocarbon, but X into which a heteroatom or a hetero bond is introduced may be used for imparting various properties.

[0014] As the polycarbonate resin (A), an aromatic polycarbonate resin is particularly preferable. The aromatic polycarbonate resin refers to a polycarbonate resin in which the carbon directly bonded to the carbonate bond is each an aromatic carbon. Among various polycarbonates, the aromatic polycarbonate is excellent from the viewpoints of heat resistance, mechanical properties, electrical properties, etc.

[0015] There is no limitation on the specific type of the aromatic polycarbonate resin. For example, an aromatic polycarbonate polymer obtained by reacting a dihydroxy compound with a carbonate precursor can be mentioned. At this time, in addition to the dihydroxy compound and the carbonate precursor, a polyhydroxy compound or the like may be reacted. Further, a method of reacting carbon dioxide as a carbonate precursor with a cyclic ether may also be used. The aromatic polycarbonate polymer may be linear or branched. Furthermore, the aromatic polycarbonate polymer may be a homopolymer composed of one kind of repeating unit, or may be a copolymer having two or more kinds of repeating units. At this time, various copolymerization forms such as a random copolymer and a block copolymer can be selected for the copolymer. Usually, such an aromatic polycarbonate polymer becomes a thermoplastic resin.

[0016] Among the monomers used as raw materials for the aromatic polycarbonate resin, examples of the aromatic dihydroxy compound include dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (that is, resorcinol), and 1,4-dihydroxybenzene;

[0017] dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl;

[0018] dihydronaphthalenes 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;

[0019] 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, 1,3-bis(4-hydroxyphenoxy)benzene;

[0020] 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C), 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(3,5-dimethyl-4-hydroxyphenyl)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, 1,1-Bis(4-hydroxyphenyl)-1-phenylethane, 1,1-Bis(4-hydroxyphenyl)-1-naphthylethane, 1,1-Bis(4-hydroxyphenyl)butane, 2,2-Bis(4-hydroxyphenyl)butane, 2,2-Bis(4-hydroxyphenyl)pentane, 1,1-Bis(4-hydroxyphenyl)hexane, 2,2-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, 1,1-Bis(4-hydroxyphenyl)decane, 1,1-Bis(4-hydroxyphenyl)dodecane, and other bis(hydroxyaryl)alkanes;

[0021] 1,1-Bis(4-hydroxyphenyl)cyclopentane, 1,1-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)-4-tert-butyl-cyclohexane, 1,1-Bis(4-hydroxyphenyl)-3-phenylcyclohexane, 1,1-Bis(4-hydroxyphenyl)-4-phenylcyclohexane, and other bis(hydroxyaryl) cycloalkanes;

[0022] 9,9-Bis(4-hydroxyphenyl)fluorene, and other bisphenols containing a cardo structure, such as 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

[0023] 4,4'-Dihydroxydiphenyl sulfide, and other dihydroxydiaryl sulfides, such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide;

[0024] and other dihydroxydiaryl sulfoxides, such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide;

[0025] 4,4'-Dihydroxydiphenyl sulfone, and other dihydroxydiaryl sulfones, such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone; etc. may be mentioned.

[0026] In addition, as for the aromatic dihydroxy compound, one kind may be used, or two or more kinds may be used in combination at an arbitrary combination and ratio. Among these, bis(hydroxyaryl) alkanes are preferable, and among them, bis(4-hydroxyphenyl) alkanes are preferable. Particularly from the viewpoints of impact resistance and heat resistance, 2,2-bis(4-hydroxyphenyl)propane (that is, bisphenol A), 2,2-bis(3-methyl-4-hydroxyphenyl)propane (that is, bisphenol C) are preferable, and a polymer using one of them alone, or a copolymer using both of them in combination, or a mixture of these (co)polymers is preferable.

[0027] Examples of monomers used as raw materials for aliphatic polycarbonate resins include 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;

[0028] 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;

[0029] glycols such as ethylene glycol, 2,2'-oxydiethanol (i.e., diethylene glycol), triethylene glycol, propylene glycol, and spiroglycol;

[0030] aralkyl diols 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;

[0031] 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. can be mentioned.

[0032] Among the monomers that are raw materials for polycarbonate resins, examples of carbonate precursors include carbonyl halides, carbonate esters, etc. Note that one type of carbonate precursor may be used, or two or more types may be used in combination at any combination and ratio.

[0033] Specific examples of carbonyl halides include, for example, phosgene; haloformates such as bischloroformate of dihydroxy compounds, monochloroformate of dihydroxy compounds, etc. Specific examples of carbonate esters include, for example, diaryl carbonates such as diphenyl carbonate, ditolyl carbonate; dialkyl carbonates such as dimethyl carbonate, diethyl carbonate; carbonate bodies of dihydroxy compounds such as biscarbonate of dihydroxy compounds, monocarbonate of dihydroxy compounds, cyclic carbonates, etc.

[0034] The method for producing polycarbonate resin is not particularly limited, and any known method can be adopted. Examples thereof include the interfacial polymerization method, the melt transesterification method, the pyridine method, the ring-opening polymerization method of cyclic carbonate compounds, the solid-phase transesterification method of prepolymers, etc.

[0035] The molecular weight of the polycarbonate resin (A) is arbitrary and can be appropriately selected and determined. However, it is preferably 10,000 to 40,000 in terms of the viscosity-average molecular weight [Mv]. If the viscosity-average molecular weight is less than 10,000, the mechanical strength tends to be insufficient. If the viscosity-average molecular weight exceeds 40,000, the fluidity is poor and the moldability tends to deteriorate. The viscosity-average molecular weight is more preferably 16,000 to 40,000, still more preferably 18,000 to 30,000, and particularly preferably 18,500 to 25,000. To adjust the viscosity-average molecular weight within such a range, it is possible by known methods such as controlling the amount of the molecular weight regulator as described later.

[0036] Here, the viscosity-average molecular weight [Mv] means a value calculated from the intrinsic viscosity [η] (unit: dl / g) at 25 °C using an Ubbelohde viscometer with methylene chloride as the solvent, according to Schnell's viscosity formula, that is, η = 1.23×10 -4 Mv 0.83 The intrinsic viscosity [η] is a value calculated by measuring the specific viscosity [ηsp] at each solution concentration [C] (g / dl) according to the following formula.

Equation

[0037] Other matters regarding the polycarbonate resin The terminal hydroxyl group concentration of the polycarbonate resin is arbitrary and can be appropriately selected and determined. However, it is usually 1000 ppm or less, preferably 800 ppm or less, and more preferably 600 ppm or less. By doing so, the retention thermal stability and color tone of the polycarbonate resin composition can be further improved. Also, the lower limit is usually 10 ppm or more, preferably 30 ppm or more, and more preferably 40 ppm or more, particularly for polycarbonate resins produced by the melt transesterification method. This can suppress the decrease in molecular weight and further improve the mechanical properties of the polycarbonate resin composition. The unit of the terminal hydroxyl group concentration is the mass of the terminal hydroxyl group expressed in ppm with respect to the mass of the polycarbonate resin. The measurement method is carried out by colorimetric determination using the titanium tetrachloride / acetic acid method (the method described in Macromol.Chem. 88 215 (1965)).

[0038] Note that the polycarbonate resin (A) is not limited to an embodiment containing only one type of polycarbonate resin, and two or more polycarbonate resins having different monomer compositions, molecular weights, terminal hydroxyl group concentrations, etc. may be mixed and used. Further, it may be used in combination as an alloy (mixture) in which another thermoplastic resin is mixed with the polycarbonate resin.

[0039] Furthermore, for example, for the purpose of further enhancing flame retardancy and impact resistance, the polycarbonate resin is a copolymer with an oligomer or polymer having a siloxane structure; for the purpose of further improving thermal oxidation stability and flame retardancy, a copolymer with a monomer, oligomer or polymer having a phosphorus atom; for the purpose of improving thermal oxidation stability, a copolymer with a monomer, oligomer or polymer having a dihydroxyanthraquinone structure; for the purpose of improving optical properties, a copolymer with an oligomer or polymer having an olefinic structure such as polystyrene; a copolymer with a polyester resin oligomer or polymer for the purpose of improving chemical resistance; etc., and may be configured as a copolymer mainly composed of a polycarbonate resin.

[0040] In addition, in order to improve the appearance and fluidity of the molded product, the polycarbonate resin may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1500 or more, preferably 2000 or more, and usually 9500 or less, preferably 9000 or less. Further, the content of the polycarbonate oligomer is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer).

[0041] Furthermore, the polycarbonate resin may be not only virgin raw materials but also polycarbonate resins recycled from used products (so-called material-recycled polycarbonate resins). Examples of the used products include optical recording media such as optical discs; light guide plates; vehicle transparent members such as automotive window glass, automotive headlamp lenses, and windshields; containers such as water bottles; spectacle lenses; and building members such as soundproof walls, glass windows, and corrugated sheets. Also, pulverized products obtained from defective products, sprues, runners, etc. of products or pellets obtained by melting them can also be used. However, the recycled polycarbonate resin is preferably 80% by mass or less, more preferably 50% by mass or less, of the polycarbonate resin contained in the polycarbonate resin composition. Since the recycled polycarbonate resin is likely to have undergone deterioration such as thermal degradation and aging degradation, if such a polycarbonate resin is used in an amount exceeding the above range, the hue and mechanical properties may be deteriorated.

[0042] [Graft copolymer (B) containing aromatic vinyl monomer component (b1), vinyl cyanide monomer component (b2), and diene rubbery polymer component (b3)] The graft copolymer (B) contained in the polycarbonate resin composition of the present invention is a graft copolymer containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2), and a diene rubbery polymer component (b3). The graft copolymer (B) preferably consists of 40 to 80% by mass of the aromatic vinyl monomer component (b1), 10 to 30% by mass of the vinyl cyanide monomer component (b2), and 10 to 50% by mass of the diene rubbery polymer component (b3), and may further contain 0 to 30% by mass of other monomer components (b4).

[0043] Examples of the aromatic vinyl monomer component (b1) in the graft copolymer (B) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, tribromostyrene, etc. Among them, styrene is particularly preferred. The proportion of the aromatic vinyl monomer component (b1) in the graft copolymer (B) is preferably in the range of 40 to 80% by mass, more preferably 45% by mass or more, still more preferably 50% by mass or more, particularly preferably 55% by mass or more, more preferably 75% by mass or less, still more preferably 70% by mass or less, and particularly preferably 65% by mass or less in 100% by mass of the graft copolymer (B).

[0044] Examples of the vinyl cyanide monomer component (b2) in the graft copolymer (B) include acrylonitrile, methacrylonitrile, etc. Among them, acrylonitrile is particularly preferred. The proportion of the vinyl cyanide monomer component (b2) in the graft copolymer (B) is preferably in the range of 10 to 30% by mass, more preferably 12% by mass or more, still more preferably 14% by mass or more, particularly preferably 15% by mass or more, more preferably 28% by mass or less, still more preferably 26% by mass or less, and particularly preferably 25% by mass or less in 100% by mass of the graft copolymer (B).

[0045] Examples of the diene rubber polymer component (b3) of the graft copolymer (B) include rubber components such as polybutadiene, polyisoprene, styrene-butadiene copolymer, etc. The proportion of the diene rubber polymer component (b3) in the graft copolymer (B) is preferably in the range of 10 to 50% by mass, more preferably 13% by mass or more, still more preferably 14% by mass or more, particularly preferably 15% by mass or more, and more preferably 45% by mass or less in 100% by mass of the graft copolymer (B).

[0046] Furthermore, it may be a copolymerization product with other monomer components (b4) copolymerizable therewith. In this case, examples of other vinyl monomers copolymerizable therewith include maleimide-based monomers such as maleimide, N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, acrylamide-based monomers such as acrylamide and N-methylacrylamide, unsaturated acid anhydrides such as maleic anhydride and itaconic anhydride, unsaturated acids such as acrylic acid and methacrylic acid, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methoxypolyethylene glycol methacrylate, and the like. The proportion of the other monomer component (b4) in the graft copolymer (B) is preferably in the range of 0 to 30% by mass, more preferably 20% by mass or less, still more preferably 10% by mass or less, particularly preferably 5% by mass or less, especially 3% by mass or less, and most preferably 2% by mass or less in 100% by mass of the graft copolymer (B).

[0047] Specific examples of the graft copolymer (B) preferably include acrylonitrile-butadiene-styrene graft copolymer, acrylonitrile-butadiene-styrene-α-methylstyrene graft copolymer, acrylonitrile-ethylene-propylene-diene-styrene copolymer, etc. Among them, acrylonitrile-butadiene-styrene graft copolymer (ABS resin) is particularly preferred.

[0048] The graft copolymer (B) is usually produced by methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, and can be used regardless of the production method.

[0049] The content of the graft copolymer (B) is 10 to 45 parts by mass, preferably 12 parts by mass or more, more preferably 15 parts by mass or more, preferably 42 parts by mass or less, and more preferably 40 parts by mass or less, based on 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). By having the content within such a range, the resin composition can be made excellent in heat resistance and fluidity. When the amount of the graft copolymer (B) exceeds 45 parts by mass, the heat resistance decreases, and when it is less than 10 parts by mass, the fluidity decreases.

[0050] [Ethylene-(meth)acrylate copolymer (C)] The ethylene-(meth)acrylate copolymer (C) contained in the polycarbonate resin composition of the present invention has a proportion of structural units derived from the (meth)acrylate ester of more than 0% by mass and less than 20% by mass. In the present invention, by incorporating such an ethylene-(meth)acrylate copolymer (C) having a specific amount of units derived from the (meth)acrylate ester into the alloy of the polycarbonate resin (A) and the graft copolymer (B), the generation of rattling noise (abnormal noise) is reduced, and even when used for a long period in a high-temperature environment as vehicle parts or the like, the generation of rattling noise (abnormal noise) is reduced, enabling a polycarbonate resin composition excellent in self-tapping property.

[0051] In this specification, “(meth)acryl” means at least either “acryl” or “methacryl”.

[0052] The ethylene-(meth)acrylate copolymer (C) may contain other α-olefins in addition to ethylene, and examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc., but ethylene alone is preferred.

[0053] Examples of the (meth)acrylic acid ester of the ethylene-(meth)acrylic acid ester copolymer (C) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. Among them, methyl acrylate, ethyl acrylate, and methyl methacrylate are preferable, ethyl acrylate and methyl methacrylate are more preferable, and ethyl acrylate is particularly preferable.

[0054] In the ethylene-(meth)acrylic acid ester copolymer (C), the content ratio of the structural unit derived from the (meth)acrylic acid ester is more than 0% by mass and 20% by mass or less. By having the content ratio of the structural unit derived from the (meth)acrylic acid ester in such a small range, it becomes possible to achieve both good rolling sound characteristics and excellent self-tapping properties for the first time. When the content ratio of the structural unit derived from the (meth)acrylic acid ester is 20% by mass or more, the structural unit derived from the (meth)acrylic acid ester is liable to oxidatively deteriorate, and particularly deteriorates in a high-temperature environment, easily generating abnormal sounds. The preferable upper limit of the content ratio of the structural unit derived from the (meth)acrylic acid ester is 19% by mass, more preferably 18% by mass, the preferable lower limit is 0.5% by mass, more preferably 1% by mass, particularly 2% by mass, 3% by mass, 4% by mass, and particularly preferably 5% by mass.

[0055] The MFR of the ethylene-(meth)acrylic acid ester copolymer (C) is preferably less than 10 g / 10 min, more preferably less than 8 g / 10 min, and preferably 1 g / 10 min or more, more preferably 2 g / 10 min or more, and 3 g / 10 min or more. Here, the MFR is the melt flow rate (MFR) measured at a temperature of 190 °C under a load of 21.18 N in accordance with JIS K7210 (1995).

[0056] The content of the ethylene-(meth)acrylate copolymer (C) is 1.5 to 5.5 parts by mass with respect to 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). With such a content, it is possible to achieve both the chatter noise (abnormal noise) characteristics and the self-tapping property while maintaining mechanical properties such as impact resistance. When the content is low, as described later, the abnormal noise risk index becomes high both initially and after aging, and when the content is too high, the self-tapping property deteriorates. The content of the ethylene-(meth)acrylate copolymer (C) is preferably 2 parts by mass or more, more preferably 2.5 parts by mass or more.

[0057] [Stabilizer] The polycarbonate resin composition of the present invention preferably contains a stabilizer, and as the stabilizer, a phosphorus-based stabilizer or a phenol-based stabilizer is preferable.

[0058] As the phosphorus-based stabilizer, any known one can be used. Specific examples include oxo acids of phosphorus such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; acidic metal 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 phosphite compounds, organic phosphonite compounds, etc. Among them, organic phosphite compounds are particularly preferable.

[0059] Examples of the organic phosphite compound include triphenyl phosphite, tris(monononylphenyl) phosphite, tris(monononyl / dinonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecylmonophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl) octyl phosphite, etc. Examples of such organic phosphite compounds include, specifically, "ADEKA STAB 1178", "ADEKA STAB 2112", "ADEKA STAB HP-10" manufactured by ADEKA Corporation, "JP-351", "JP-360", "JP-3CP" manufactured by Johoku Chemical Industry Co., Ltd., "IRGAFOS 168" manufactured by BASF, and the like. Note that one type of phosphorus-based stabilizer may be contained, or two or more types may be contained in any combination and ratio.

[0060] The content of the phosphorus-based stabilizer is usually 0.001 part by mass or more, preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, and usually 1 part by mass or less, preferably 0.7 part by mass or less, more preferably 0.5 part by mass or less, based on 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). When the content of the phosphorus-based stabilizer is less than the lower limit of the above range, the thermal stability effect may be insufficient. When the content of the phosphorus-based stabilizer exceeds the upper limit of the above range, the effect may reach a plateau and become uneconomical.

[0061] Examples of phenolic stabilizers 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, thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 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.

[0062] Among them, 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 such phenolic antioxidants include, for example, "Irganox 1010" and "Irganox 1076" manufactured by BASF, and "Adekastab AO-50" and "Adekastab AO-60" manufactured by ADEKA. In addition, one phenolic stabilizer may be contained, or two or more phenolic stabilizers may be contained in any combination and ratio.

[0063] The content of the phenolic stabilizer 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 part by mass or less, based on 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). By setting the content of the phenolic stabilizer to be equal to or higher than the lower limit value of the above range, the effect as a phenolic stabilizer can be sufficiently obtained. Further, by setting the content of the phenolic stabilizer to be equal to or lower than the upper limit value of the above range, it is economical without the effect reaching a plateau.

[0064] [Release agent] Moreover, the polycarbonate resin composition of the present invention preferably contains a release agent (lubricant). Examples of the release agent include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, polysiloxane-based silicone oils, and the like.

[0065] Examples of the aliphatic carboxylic acid include saturated or unsaturated aliphatic monovalent, divalent, or trivalent carboxylic acids. Here, the aliphatic carboxylic acid also includes alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and more preferably aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetratriacontanoic acid, montanic acid, adipic acid, azelaic acid, and the like.

[0066] As the aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol, for example, the same as the above aliphatic carboxylic acid can be used. On the other hand, examples of the alcohol include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms and aryl groups. Among these, monohydric or polyhydric saturated alcohols having 30 or fewer carbon atoms are preferred, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or fewer carbon atoms are more preferred. Here, aliphatic is used as a term that also includes alicyclic compounds.

[0067] 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, dipentaerythritol, and the like.

[0068] In addition, the above ester may contain an aliphatic carboxylic acid and / or an alcohol as impurities. Also, the above ester may be a pure substance or a mixture of a plurality of compounds. Further, for the aliphatic carboxylic acid and the alcohol that combine to form one ester, each may use one kind, or two or more kinds may be used in combination in any combination and ratio.

[0069] Specific examples of the ester of an aliphatic carboxylic acid and an alcohol include beeswax (a mixture mainly composed of myricyl palmitate), stearyl stearate, behenyl behenate, behenyl stearate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, and the like.

[0070] Examples of the polysiloxane-based silicone oil include dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil, fluorinated alkyl silicone, and the like.

[0071] In addition, the above-described release agent may contain one kind, or may contain two or more kinds in any combination and ratio.

[0072] The content of the release agent 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, based on 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). By setting the content of the release agent to be not less than the lower limit value of the above range, the effect of releasability can be easily obtained sufficiently, and by setting the content of the release agent to be not more than the upper limit value of the above range, mold contamination during injection molding and the like are less likely to occur.

[0073] [Other Components] The polycarbonate resin composition of the present invention may contain other components in addition to those described above, if necessary, as long as the desired physical properties are not significantly impaired. Examples of other components include other resins other than the polycarbonate resin (A), the graft copolymer (B), and the ethylene-(meth)acrylate copolymer (C), various resin additives, and the like. In addition, one kind of other components may be contained, or two or more kinds may be contained in any combination and ratio.

[0074] Examples of other resins include thermoplastic polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate resin, and polybutylene terephthalate resin; styrene resins such as polystyrene resin, high-impact polystyrene resin (HIPS), and acrylonitrile-styrene copolymer (AS resin); polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; polysulfone resin; polymethacrylate resin, and the like. Note that one kind of other resin may be contained, or two or more kinds may be contained in any combination and ratio.

[0075] When containing other resins other than the above (A) to (C), the content is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less with respect to 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B).

[0076] Examples of other resin additives other than those described above include ultraviolet absorbers, dyes and pigments (including titanium oxide and carbon black), antistatic agents, fillers, flame retardants, antifogging agents, antiblocking agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, and the like. Note that one kind of other resin additive may be contained, or two or more kinds may be contained in any combination and ratio.

[0077] [Manufacture of Polycarbonate Resin Composition] There is no restriction on the method for producing the polycarbonate resin composition of the present invention, and known methods for producing polycarbonate resin compositions can be widely adopted. The above-described essential components and other components that are blended as necessary are, for example, premixed using various mixers such as tumblers and Henschel mixers, and then melt-kneaded using mixers such as Banbury mixers, rolls, Brabenders, single-screw kneading extruders, twin-screw kneading extruders, and kneaders. The temperature for melt-kneading is not particularly limited, but is usually in the range of 240 to 320°C.

[0078] The polycarbonate resin composition of the present invention generates less abnormal noise and is excellent in self-tapping properties. The polycarbonate resin composition of the present invention preferably has a shear strength of 19 MPa or more based on JIS K7214. Shear strength is related to self-tapping properties, and the higher the shear strength, the better the resistance to material breakage during screw tightening, that is, the self-tapping breakage torque. The upper limit of the shear strength is preferably 30 MPa or less. The polycarbonate resin composition of the present invention preferably has a noise risk index (RPN) in the range of 1 to 3 based on VDA203 - 206 of the German Automobile Industry Association, and particularly preferably 1. Since the polycarbonate resin composition of the present invention is excellent in self-tapping properties, the self-tapping breakage torque is preferably 1.00 N·m or more, more preferably 1.05 N·m or more, and particularly preferably 1.10 N·m or more. The details of each of the above specific measurement methods are as described in the examples.

[0079] [Molded article] There is no limitation on the method for manufacturing a molded article from the obtained resin composition pellets, and any molding method generally adopted for polycarbonate resin compositions can be arbitrarily adopted. Examples thereof include injection molding, ultra-high-speed injection molding, injection compression molding, two-color molding, hollow molding such as gas assist, molding method using an adiabatic mold, molding method using a rapid heating mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, and the like. From the viewpoints of easy molding and productivity, injection molding and injection compression molding are preferred.

[0080] Molded articles formed from the polycarbonate resin composition generate little rattling noise (abnormal noise), generate little rattling noise (abnormal noise) even when used for a long time in a high-temperature environment, and are also excellent in self-tapping property. Therefore, molded articles formed from the polycarbonate resin composition of the present invention can be suitably used as parts that come into contact with each other or other molded articles, such as parts in the automotive field, OA equipment field, household appliances, electric and electronic fields, etc., and are particularly suitable for use as automotive interior parts.

[0081] When a molded article of the polycarbonate resin composition of the present invention is used as an automotive interior part, when the parts come into contact with each other or with other parts due to the vibration of the automobile, it is possible to significantly reduce the generation of squeaking noise. Such automotive interior parts include, for example, in-vehicle displays, car navigation systems, car audio systems, dashboards, instrument panels, overhead consoles, interior light panels, meter panels, door trims, roof trims, switch panels, door linings, decoration panels, indicator panels, front pillar garnishes, center pillar upper garnishes, rear pillar garnishes, cowl side garnishes, front rear side garnishes, center pillar lower garnishes and other pillar garnishes, pillar trims, center consoles, console boxes, inner panels, door pockets, armrest bases, grab rails, assist grips, column covers, ventilators, ducts, air conditioners, switch parts, cup holders, sub-trunks, glove boxes, trunk side trims, trunk side linings, tailgate linings, rear panels, etc.

Examples

[0082] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not construed as being limited to the following examples. The raw material components used in the examples and comparative examples are as shown in Table 1 below.

[0083]

Table 1

[0084] [Examples 4 ~9 , Reference Examples 1 to 3 , Comparative Examples 1 to 10] Each component described in Table 1 above was blended so as to have the ratios (mass ratios) described in Tables 2 to 3 below, and uniformly mixed in a tumbler to obtain a mixture. This mixture was supplied to a twin-screw extruder ("TEM26SX" manufactured by Toshiba Machine Co., Ltd.), kneaded under the conditions of a screw rotation speed of 150 rpm, a discharge rate of 25 kg / h, and a barrel temperature of 260°C, and extruded in a strand form from the tip of the extrusion nozzle. The strand was rapidly cooled in a water tank, cut using a pelletizer to form pellets, and pellets of the polycarbonate resin composition were obtained.

[0085] <Abnormal noise risk index (RPN)> The pellets obtained by the above method were injection molded using an injection molding machine "EC50SXII" manufactured by Toshiba Machine Co., Ltd. under the conditions of a cylinder temperature of 260°C and a mold temperature of 60°C to obtain a molded product (large test piece) with a length of 60 mm, a width of 60 mm, and a thickness of 3 mm. Separately, small test pieces with a length of 50 mm, a width of 25 mm, and a thickness of 3 mm were cut out from the large test piece using a disk saw. Next, after chamfering the ends of the test pieces with #100 sandpaper, fine burrs were removed with a cutter knife to obtain small test pieces for evaluating the squeaking noise.

[0086] The obtained large test piece was set on the movable stage of a stick-slip tester "SSP-04" manufactured by ZIEGLER, and the small test piece was set on the fixed stage. Based on the German Automobile Industry Association standard VDA230-206, at a temperature of 23°C, a humidity of 50% RH, the load (N) and speed (mm / sec) described in Tables 2 to 3, the abnormal noise risk index (also referred to as the abnormal noise generation risk. RPN) when rubbing against each other 3 times with an amplitude of 20 mm was measured. In addition, the large and small test pieces for the above evaluation were left in a constant temperature bath at 85°C for 200 hours (heat treatment), and after cooling at 25°C for 24 hours, for the heat-treated evaluation test pieces, in the same manner as above, the abnormal noise risk index after heat treatment was obtained.

[0087] The abnormal noise risk index (RPN) is displayed in 10 steps on a scale of 1 to 10 by the said device. A smaller numerical value of the abnormal noise risk index means that the squeaking noise is less likely to occur, and the larger the value, the more likely the squeaking noise is to occur. According to the German Automobile Industry Association standard VDA230-206, if the abnormal noise risk index is between 1 and 3, the risk of generating a crunching sound is low, and it is considered to meet the qualified level as a practical product. Judgment was made based on the following criteria A to C from the obtained abnormal noise risk index (RPN). A: The highest abnormal noise risk index under the tested conditions is between 1 and 3 B: The highest abnormal noise risk index under the tested conditions is between 4 and 5 C: The highest abnormal noise risk index under the tested conditions is between 6 and 10

[0088] <Shear strength (unit: MPa)> An 11-mm hole was drilled at the center of the large test piece with a length of 60 mm, a width of 60 mm, and a thickness of 3 mm obtained above to obtain a test piece. For this, based on JIS K7214, the shear strength (unit: MPa) was measured.

[0089] <Screw tightening test: Self-tapping break torque (unit: N·m)> After drying the pellets obtained above at 100 °C for 5 hours, using an injection molding machine (Sumitomo Heavy Industries, Ltd.'s "SE50DUZ"), at a cylinder set temperature of 240 to 260 °C and a mold temperature of 60 °C, a self-tapping test boss hole test piece with a boss hole having an outer diameter of 7.5 mm × an inner diameter of 2.5 mm × a height of 10 mm formed in a plate-shaped part with dimensions of 70 mm × 45 mm × 3 mm was injection molded. A screw (M3 × 8 P type, thread major diameter 3.02 mm, thread minor diameter 2.17 mm) was screwed into the boss hole of the obtained test piece using a torque driver, and the torque at which the boss hole causes female thread breakage and reaches "screw failure" was measured and taken as the self-tapping break torque (unit: N·m). Judgment was made based on the following criteria A and C from the obtained self-tapping break torque. A: The self-tapping break torque is 1.00 or more C: The self-tapping break torque is less than 1.00

[0090] The above evaluation results are shown in Tables 2 to 3 below.

Table 2

[0091]

Table 3

Industrial Applicability

[0092] The molded article formed from the polycarbonate resin composition of the present invention generates little rattling noise (abnormal noise) and is excellent in self-tapping property. Therefore, it can be suitably used as parts that come into contact with each other or other molded articles, such as parts in the automotive field, OA equipment field, home appliances, electric and electronic fields, etc. In particular, it can be particularly suitably used as automotive interior parts.

Claims

1. 55 to 90 parts by mass of a polycarbonate resin (A), and 10 to 45 parts by mass of a graft copolymer (B) containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2), and a diene rubber polymer component (b3) are contained. Based on 100 parts by mass in total of (A) and (B), 1.5 to 5.5 parts by mass of an ethylene-(meth)acrylate copolymer (C) is contained. When containing other resins other than the above (A) to (C), the content is 3 parts by mass or less based on 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). The ratio of the structural unit derived from the (meth)acrylate ester of the ethylene-(meth)acrylate copolymer (C) is 18% by mass or more and less than 20% by mass. The abnormal noise risk index (RPN) based on VDA203 - 206 of the German Automobile Industry Association is 1 or 2 when rubbed three times under the conditions of load: 10 N and 40 N, speed: 1 mm / second and 4 mm / second, and amplitude: 20 mm. A polycarbonate resin composition characterized by this.

2. The polycarbonate resin composition according to Claim 1, having a shear strength of 19 MPa or more based on JIS K7214.

3. A molded article made of the polycarbonate resin composition according to Claim 1 or 2.

4. The molded article according to Claim 3, wherein the molded article is an automotive interior part.

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