Thermoplastic resin composition and molded article thereof

Abstract

Provided is a thermoplastic resin molded product that satisfies the required properties of high rigidity, high impact resistance, high heat resistance, low coefficient of linear thermal expansion, good molded appearance, and good painted appearance in a well-balanced manner. [Solution] A thermoplastic resin composition containing a polycarbonate (A) and wollastonite (B), characterized in that the wollastonite (B) has been treated with a silane coupling agent containing a linear alkyl group having 12 or more carbon atoms. The thermoplastic resin composition may further contain a graft copolymer (C), a vinyl copolymer (D), an ultra-high molecular weight resin (E), and a Teflon resin (F).

Description

Technical Field

[0001] The present invention relates to a thermoplastic resin composition in which wollastonite is blended as an inorganic filler in a polycarbonate resin to increase rigidity and reduce the linear thermal expansion coefficient, and suppresses a decrease in impact resistance due to the blending of the inorganic filler, and thermoplastic resin composition with well-balanced improvement of high rigidity, low linear thermal expansion coefficient and high impact resistance in a high dimension, and a molded article formed by molding this thermoplastic resin composition.

Background Art

[0002] Polycarbonate resins, particularly aromatic polycarbonate resins, have excellent mechanical properties such as moldability and impact resistance, dimensional stability, and also excellent appearance of molded articles. Therefore, conventionally, polycarbonate resins alone or resin compositions alloyed with ABS resins or AS resins have been used as molding materials in a wide range of industrial fields such as electrical and electronic parts and vehicles.

[0003] In recent years, in response to the demand for weight reduction of vehicles such as automobiles, technologies for replacing vehicle parts with resin materials have spread. For polycarbonate resins or polycarbonate resin compositions, in order to achieve the high rigidity and low linear thermal expansion coefficient required for these applications, inorganic fillers are blended into these resins (for example, Patent Documents 1 to 3). Various inorganic fillers such as talc, wollastonite, and glass fiber are available, and in order to improve the compatibility with the resin and enhance the blending effect, the inorganic filler is also surface-treated with a silane coupling agent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] For vehicle parts such as automobiles, especially resin compositions for exterior parts, high rigidity, high impact resistance, high heat resistance, low linear thermal expansion coefficient, good molding appearance, and good painting appearance are required. However, in reality, there is no resin composition that can satisfy all these required characteristics well in balance. That is, in the prior art, the rigidity can be increased by blending an inorganic filler, but when the blending amount of the inorganic filler is increased to further increase the rigidity, the impact resistance is extremely reduced. Also, the molding appearance and painting appearance are impaired.

[0006] The present invention has been made in view of such conventional problems, and an object thereof is to provide a thermoplastic resin composition that can satisfy the required characteristics of high rigidity, high impact resistance, high heat resistance, low linear thermal expansion coefficient, and further good molding appearance and good painting appearance in a high-dimensional and well-balanced manner, and a molded article using the same.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventor has found that by using wollastonite treated with a specific silane coupling agent as a reinforcing inorganic filler for a polycarbonate resin, high rigidity and high impact resistance can be achieved in a high-dimensional and compatible manner. Furthermore, by blending a specific ultra-high molecular weight resin or Teflon-based resin into the resin composition, the molding appearance and painting appearance can be improved, and the above problems can be solved, thus completing the present invention. That is, the gist of the present invention is as follows.

[0008] [1] A thermoplastic resin composition containing a polycarbonate resin (A) and wollastonite (B), wherein the wollastonite (B) is treated with a silane coupling agent containing a linear alkyl group having 12 or more carbon atoms.

[0009] [2] Furthermore, the thermoplastic resin composition according to [1], which contains a graft copolymer (C) or a vinyl copolymer (D) obtained by copolymerizing the graft copolymer (C) with at least an aromatic vinyl monomer and a vinyl cyanide monomer.

[0010] [3] The thermoplastic resin composition according to [2], wherein the graft copolymer (C) is a rubber-reinforced styrene acrylonitrile graft copolymer obtained by graft-polymerizing a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of a diene rubber polymer.

[0011] [4] The thermoplastic resin composition according to [2] or [3], which contains 45 to 65 parts by mass of a polycarbonate resin (A), 15 to 40 parts by mass of an inorganic filler containing wollastonite (B), 7 to 20 parts by mass of a graft copolymer (C), and 0 to 20 parts by mass of a vinyl copolymer (D), with the total of these being 100 parts by mass.

[0012] [5] The thermoplastic resin composition according to any one of [2] to [4], which further contains a ultra-high molecular weight resin (E) having a weight average molecular weight of 2 million or more or a Teflon resin (F), which is different from the polycarbonate resin (A), the graft copolymer (C), and the vinyl copolymer (D).

[0013] [6] A molded article obtained by molding the thermoplastic resin composition according to any one of [1] to [5].

[0014] [7] The molded article according to [6], which is an exterior part of a vehicle. [Advantages of the Invention]

[0015] According to the thermoplastic resin composition of the present invention, it is possible to provide a thermoplastic resin molded article that highly dimensionally and well-balancedly satisfies the required characteristics of high rigidity, high impact resistance, high heat resistance, low linear thermal expansion coefficient, and furthermore, good molding appearance and good coating appearance. [Embodiments for Carrying Out the Invention]

[0016] The embodiments of the present invention will be described in detail below.

[0017] [Thermoplastic resin composition] The thermoplastic resin composition of the present invention is a thermoplastic resin composition containing polycarbonate (A) and wollastonite (B), characterized in that the wollastonite (B) is treated with a silane coupling agent containing a linear alkyl group having 12 or more carbon atoms. The thermoplastic resin composition of the present invention may further contain a graft copolymer (C), a vinyl copolymer (D), an ultra-high molecular weight resin (E) or a Teflon-based resin (F). Further, it may contain an inorganic filler other than wollastonite (B).

[0018] In the present invention, “(co)polymerization” means homopolymerization and copolymerization, and “(meth)acrylate” means at least one of acrylate and methacrylate. The same applies to “(meth)acrylic acid”.

[0019] [Polycarbonate resin (A)] As the polycarbonate resin (A), those obtained by known polymerization methods such as the interfacial polycondensation method of a dihydroxy compound such as a dihydroxyaryl compound and phosgene, and the transesterification reaction (melt polycondensation) of a dihydroxy compound such as a dihydroxyaryl compound and a carbonate compound such as diphenyl carbonate can all be used. From the viewpoint of mechanical strength such as impact resistance, the polycarbonate resin (A) is preferably an aromatic polycarbonate resin (A).

[0020] Examples of the above dihydroxyaryl compound include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxyphenyl ether, 4,4'-dihydroxyphenyl sulfide, 4,4'-dihydroxyphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, hydroquinone, resorcinol, etc. Further, there are hydroxyaryloxy-terminated polyorganosiloxanes (see, for example, U.S. Patent No. 3,419,634). These can be used alone or in combination of two or more. Among these, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is preferred.

[0021] The viscosity average molecular weight of the polycarbonate resin (A) is preferably 12,000 to 40,000, more preferably 15,000 to 35,000, and particularly preferably 18,000 to 30,000. A higher molecular weight results in higher mechanical strength of the molded product, but the fluidity decreases, uniform cells cannot be obtained, and the appearance of the molded product tends to deteriorate. Two or more polycarbonate resins (A) having different molecular weights can also be used as the component (C).

[0022] Here, the viscosity average molecular weight of the polycarbonate resin (A) can usually be calculated by inserting the specific viscosity (ηsp) measured at 20 °C and a concentration of [0.7 g / 100 ml (methylene chloride)] using methylene chloride as a solvent into the following formula. Viscosity average molecular weight = ([η] × 8130) 1.205 Here, [η] = [((ηsp × 1.12 + 1) 1 / 2 - 1) / 0.56C]. Note that C represents the concentration.

[0023] The polycarbonate resin (A) obtained by interfacial polycondensation may contain various chlorine compounds, and this chlorine compound may have an adverse effect on the durability of the thermoplastic resin composition of the present invention. Therefore, the chlorine compound content of the polycarbonate resin (A) is usually 300 ppm or less, preferably 100 ppm or less, in terms of chlorine atoms.

[0024] [Wollastonite (B)] There are no particular restrictions on the untreated wollastonite used for wollastonite (B), and any of those generally industrially used can be used.

[0025] The wollastonite (B) treated with a silane coupling agent preferably has a mass loss rate of 0.2 to 1.7% by mass, particularly 0.3 to 1.2% by mass, when heated from 30°C to 600°C. If the mass loss rate is within the above range, the treatment effect by the silane coupling agent can be sufficiently obtained, and excellent impact resistance can be exhibited.

[0026] The wollastonite (B) used in the present invention is characterized by being treated with a silane coupling agent containing a linear alkyl group having 12 or more carbon atoms. Here, when the carbon number of the alkyl group contained in the silane coupling agent is 11 or less, or it is a branched alkyl group, or it is another substituent, the effect of achieving both high rigidity and impact resistance according to the present invention cannot be obtained. From the viewpoint of these effects, the carbon number of the alkyl group contained in the silane coupling agent is particularly preferably 12 to 20. Examples of such silane coupling agents containing an alkyl group include dodecyltriethoxysilane, dodecyltrimethoxysilane, dodecyltrichlorosilane, chlorododecyldimethylsilane, hexadecyltriethoxysilane, hexadecyltrimethoxysilane, trichlorohexadecylsilane, octadecyltriethoxysilane, octadecyltrimethoxysilane, methyldimethyloctadecylsilane, dimethyloctadecylchlorosilane, trichlorooctadecylsilane, and the like. These silane coupling agents may be used alone or in combination of two or more.

[0027] The method of surface treatment with a silane coupling agent is not particularly limited and can be carried out by methods such as dry method, wet method, integral blend, etc. Any method may be used, but the dry method or the wet method is preferred.

[0028] The amount of treatment with the silane coupling agent for wollastonite (B) is not particularly limited as long as the effects of the present invention can be obtained, but it is preferably 0.3 to 3% by mass, particularly 0.5 to 2% by mass, of the silane coupling agent based on the untreated wollastonite. If the amount of treatment with the silane coupling agent is within the above range, the treatment effect of the silane coupling agent can be sufficiently obtained, and excellent impact resistance can be exhibited.

[0029] [Graft copolymer (C)] From the viewpoint of high impact resistance, the graft copolymer (C) is preferably a rubber-reinforced styrene acrylonitrile resin obtained by polymerizing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of a rubbery polymer.

[0030] Examples of the rubber polymer include diene rubbers such as polybutadiene, polyisoprene, butadiene-styrene copolymer, and butadiene-acrylonitrile copolymer; olefin rubbers such as ethylene-propylene copolymer, ethylene-propylene-non-conjugated diene copolymer, ethylene-butene-1 copolymer, and ethylene-butene-1-non-conjugated diene copolymer; acrylic rubbers; silicone rubbers; polyurethane rubbers; silicone-acrylic IPN rubbers; natural rubber; conjugated diene block copolymers; hydrogenated conjugated diene block copolymers; and the like.

[0031] From the viewpoint of the balance between impact resistance and other physical properties, preferred rubber polymers used in the present invention are diene rubber polymers such as polybutadiene-based monomers and butadiene-styrene copolymers, and their volume average particle diameter is preferably 50 to 3000 nm, particularly preferably 50 to 2000 nm. When the volume average particle diameter is less than the above lower limit, the impact resistance tends to be inferior, and when it exceeds the above upper limit, the surface appearance of the molded product tends to be inferior.

[0032] The diene rubber-reinforced styrene acrylonitrile-based graft copolymer suitable for the present invention is obtained by graft-polymerizing a monomer mixture containing at least an aromatic vinyl-based monomer and a vinyl cyanide-based monomer in the presence of the above diene rubber polymer. The monomer mixture may contain other vinyl-based monomers copolymerizable with these in addition to the aromatic vinyl-based monomer and the vinyl cyanide-based monomer. Also, the diene rubber-reinforced styrene acrylonitrile-based graft copolymer is preferably obtained by polymerizing 80 to 30 parts by mass of a monomer mixture containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer in the presence of 20 to 70 parts by mass of the above diene rubber polymer (however, the total of the diene rubber polymer and the monomer mixture is 100 parts by mass). This ratio is more preferably 30 to 60 parts by mass of the diene rubber polymer and 70 to 40 parts by mass of the monomer mixture.

[0033] Examples of the aromatic vinyl monomer used herein include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, hydroxystyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, p-t-butylstyrene, ethylstyrene, vinylnaphthalene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethylstyrene, N,N-diethyl-p-aminoethylstyrene, vinylpyridine, etc. These can be used alone or in combination of two or more. Among these, styrene and α-methylstyrene are preferred, and styrene is particularly preferred.

[0034] Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, etc. These can be used alone or in combination of two or more. By using the vinyl cyanide monomer, chemical resistance is imparted.

[0035] The ratio of the aromatic vinyl monomer to the vinyl cyanide monomer used in the graft polymerization is by mass, aromatic vinyl monomer:vinyl cyanide monomer = 60 - 90:40 - 10, particularly preferably 70 - 80:30 - 20. Within this range, the compatibility with the polycarbonate resin (A) is improved, and an excellent balance of physical properties can be exhibited.

[0036] Examples of other vinyl monomers copolymerizable with the aromatic vinyl monomer and the vinyl cyanide monomer include (meth)acrylate ester compounds, maleimide compounds, and other various functional group-containing unsaturated compounds. Examples of the other various functional group-containing unsaturated compounds include unsaturated acid compounds, epoxy group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, acid anhydride group-containing unsaturated compounds, oxazoline group-containing unsaturated compounds, substituted or unsubstituted amino group-containing unsaturated compounds, etc. These other vinyl monomers can be used alone or in combination of two or more.

[0037] Examples of the (meth)acrylic acid ester compound include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc., and these can be used alone or in combination of two or more. By using the (meth)acrylic acid ester compound, the surface hardness is improved. The amount of the (meth)acrylic acid ester compound used is usually 0 to 75% by mass as a proportion in the monomer mixture.

[0038] Examples of the maleimide compound include maleimide, N-phenylmaleimide, N-cyclohexylmaleimide, N-cyclohexylmaleimide, etc., and these can be used alone or in combination of two or more. Also, in order to introduce a maleimide unit, maleic anhydride may be copolymerized and then imidized. By using the maleimide compound, heat resistance is imparted. The amount of the maleimide compound used is usually 0 to 30% by mass as a proportion in the total amount of the monomer mixture.

[0039] Examples of the unsaturated acid compound include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, etc., and these can be used alone or in combination of two or more.

[0040] Examples of the epoxy group-containing unsaturated compound include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, etc., and these can be used alone or in combination of two or more.

[0041] Examples of the hydroxyl group-containing unsaturated compound include 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, 3-hydroxy-3-methyl-1-propene, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, N-(4-hydroxyphenyl)maleimide, etc., and these can be used alone or in combination of two or more.

[0042] Examples of the oxazoline group-containing unsaturated compound include vinyloxazoline and the like, and these can be used alone or in combination of two or more.

[0043] Examples of the acid anhydride group-containing unsaturated compound include maleic anhydride, itaconic anhydride, citraconic anhydride, etc., and these can be used alone or in combination of two or more.

[0044] Examples of the substituted or unsubstituted amino group-containing unsaturated compound include aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, phenylaminoethyl methacrylate, N-vinyldiethylamine, N-acetylvinylamine, acrylamine, N-methylacrylamine, acrylamide, N-methylacrylamide, p-aminostyrene, etc., and these can be used alone or in combination of two or more.

[0045] When using the above-mentioned other various functional group-containing unsaturated compounds, when the polycarbonate resin (A), the graft copolymer (C), and the vinyl copolymer (D) described below are blended, the compatibility between the two may be improved. In this case, the usage amount of the above-mentioned other various functional group-containing unsaturated compounds is usually 0.1 to 20% by mass, preferably 0.1 to 10% by mass, as the total amount of the functional group-containing unsaturated compounds relative to the total of the graft copolymer (C) and the vinyl copolymer (D).

[0046] The graft copolymer (C) such as a conjugated diene rubber-reinforced styrene-acrylonitrile graft copolymer can be produced by known polymerization methods, for example, emulsion polymerization, bulk polymerization, solution polymerization, suspension polymerization, and polymerization methods combining these. In the above polymerization methods, if the rubbery polymer is obtained by emulsion polymerization, it can also be produced by emulsion polymerization in the production of the graft copolymer (C). Further, when the rubbery polymer is obtained by solution polymerization, it is generally preferable to produce the graft copolymer (C) by bulk polymerization, solution polymerization, and suspension polymerization. However, even if it is a rubbery polymer produced by solution polymerization, if the rubbery polymer is emulsified by a known method, the graft copolymer (C) can be produced by emulsion polymerization. Also, even if it is a rubbery polymer produced by emulsion polymerization, after coagulating and isolating, the graft copolymer (C) can be produced by bulk polymerization, solution polymerization, and suspension polymerization.

[0047] When producing by emulsion polymerization, a polymerization initiator, a chain transfer agent, an emulsifier, etc. are used, and all known ones can be used. Examples of the polymerization initiator include cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, tetramethylbutyl hydroperoxide, tert-butyl hydroperoxide, potassium persulfate, azobisisobutyronitrile, etc. Further, as a polymerization initiation aid, it is preferable to use various reducing agents, a redox system such as a saccharide-containing pyrophosphate iron formulation, a sulfoxylate formulation, etc.

[0048] Examples of the chain transfer agent include octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexyl mercaptan, terpinolenes, etc. Examples of the emulsifier that can be used include alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, aliphatic sulfonates such as sodium lauryl sulfate, higher fatty acid salts such as potassium laurate, potassium stearate, potassium oleate, potassium palmitate, and rosin acid salts such as potassium rosinate.

[0049] In emulsion polymerization, the method of using the rubbery polymer and the monomer mixture may be to add the monomer mixture all at once in the presence of the total amount of the rubbery polymer for polymerization, or to add it in portions or continuously for polymerization. Also, a part of the rubbery polymer may be added during the polymerization.

[0050] After emulsion polymerization, the resulting latex is usually coagulated with a coagulant. Then, by washing with water and drying, a powder of the graft copolymer (C) is obtained. At this time, after appropriately blending the latexes of two or more graft copolymers (C) obtained by emulsion polymerization, it may be coagulated, or further, after appropriately blending the latex of the vinyl copolymer (D) described below, it may be coagulated. As the coagulant, inorganic salts such as calcium chloride, magnesium sulfate, magnesium chloride, and acids such as sulfuric acid, acetic acid, citric acid, and malic acid can be used. Also, a powder of the graft copolymer (C) can be obtained by spray-drying the latex.

[0051] The solvent that can be used when producing the graft copolymer (C) by solution polymerization is an inert polymerization solvent used in ordinary radical polymerization. For example, aromatic hydrocarbons such as ethylbenzene and toluene, ketones such as methyl ethyl ketone and acetone, acetonitrile, dimethylformamide, N-methylpyrrolidone, etc. can be mentioned.

[0052] The polymerization temperature is usually in the range of 80 to 140°C, preferably 85 to 120°C. In the polymerization, a polymerization initiator may be used, or it may be polymerized by thermal polymerization without using a polymerization initiator. As the polymerization initiator, organic peroxides such as ketone peroxide, dialkyl peroxide, diacyl peroxide, peroxyester, hydroperoxide, azobisisobutyronitrile, benzoyl peroxide, etc. are preferably used. Also, when using a chain transfer agent, for example, mercaptans, terpinolenes, α-methylstyrene dimer, etc. can be used.

[0053] In addition, when producing the graft copolymer (C) by bulk polymerization or suspension polymerization, polymerization initiators, chain transfer agents, etc. described in solution polymerization can be used.

[0054] The amount of the remaining monomer in the graft copolymer (C) obtained by each of the above polymerization methods is usually 10,000 ppm or less, preferably 5,000 ppm or less.

[0055] The graft copolymer (C) obtained by graft-polymerizing a monomer mixture in the presence of a rubbery polymer contains a copolymer in which the vinyl monomer of the monomer mixture is graft-copolymerized to the rubbery polymer and an ungrafted component (a (co)polymer of a vinyl monomer) that is not grafted to the rubbery polymer.

[0056] The graft ratio of the graft copolymer (C) such as a diene rubber-reinforced styrene acrylonitrile graft copolymer is usually adjusted to 10 to 150% by mass, preferably 20 to 130% by mass, more preferably 30 to 110% by mass, and particularly preferably 40 to 100% by mass. The graft ratio can be changed by various factors such as the type and amount of the polymerization initiator, the type and amount of the chain transfer agent, the polymerization method, the contact time between the vinyl monomer and the rubbery polymer during polymerization, the rubbery polymer species, and the polymerization temperature.

[0057] The graft ratio of the graft copolymer (C), for example, a diene rubber-reinforced styrene acrylonitrile graft copolymer, can be determined by the following formula. Graft ratio (% by mass) = {(T - S) / S} × 100 In the above formula, T is the mass (g) of the insoluble matter obtained by adding 1 g of the diene rubber-reinforced styrene acrylonitrile graft copolymer to 20 ml of acetone, shaking it with a shaker for 2 hours, and then centrifuging it with a centrifuge (rotation speed: 23,000 rpm) for 60 minutes to separate the insoluble matter and the soluble matter, and S is the mass (g) of the diene rubber polymer contained in 1 g of the diene rubber-reinforced styrene acrylonitrile graft copolymer.

[0058] In addition, the intrinsic viscosity [η] of the acetone-soluble component of the graft copolymer (C) such as a diene rubber-reinforced styrene acrylonitrile graft copolymer (measured at 30 °C using methyl ethyl ketone as the solvent) is usually 0.15 to 1.2 dl / g, preferably 0.2 to 1.0 dl / g, and more preferably 0.2 to 0.8 dl / g.

[0059] The average particle diameter of the grafted rubber polymer particles dispersed in the graft copolymer (C) such as a diene rubber-reinforced styrene acrylonitrile graft copolymer is usually 50 to 3,000 nm, preferably 50 to 2,500 nm, and particularly preferably 50 to 2,000 nm. When the rubber particle diameter is less than 50 nm, the impact resistance tends to be poor, and when it exceeds 3,000 nm, the surface appearance of the molded product tends to be poor.

[0060] These graft copolymers (C) may be used alone, or two or more of them having different copolymerization compositions and physical properties may be mixed and used.

[0061] [Vinyl copolymer (D)] The vinyl copolymer (D) is obtained by copolymerizing at least an aromatic vinyl monomer and a vinyl cyanide monomer. The vinyl copolymer (D) may be one in which other vinyl monomers copolymerizable with these, other than the aromatic vinyl monomer and the vinyl cyanide monomer, are further copolymerized. As the aromatic vinyl monomer, vinyl cyanide monomer, and other vinyl monomers, all those described in the description of the graft copolymer (C) can be used. The vinyl monomers in the graft copolymer (C) and the vinyl monomers in the vinyl copolymer (D) may be the same or different.

[0062] The ratio of the aromatic vinyl monomer and the vinyl cyanide monomer constituting the vinyl copolymer (D) is, by mass, aromatic vinyl monomer:vinyl cyanide monomer = 60 to 90:40 to 10, particularly preferably 70 to 80:30 to 20. If it is within this range, the compatibility with the polycarbonate resin (A) is improved, and an excellent balance of physical properties can be exhibited.

[0063] When the total of the vinyl monomers other than the aromatic vinyl monomer and the vinyl cyanide monomer used in the copolymerization of the vinyl copolymer (D) is 100% by mass, the content is usually 75% by mass or less, preferably 50% by mass or less, and more preferably 25% by mass or less.

[0064] Preferred vinyl copolymers (D) include styrene-acrylonitrile copolymers, styrene-acrylonitrile-methyl methacrylate copolymers, and copolymers of these with the functional group-containing unsaturated compound.

[0065] The vinyl copolymer (D) can be produced by emulsion polymerization, bulk polymerization, solution polymerization, suspension polymerization, which are known polymerization methods described in the production method of the graft copolymer (C) described above, and a method combining these.

[0066] The weight average molecular weight of the vinyl copolymer (D) is usually 40,000 to 300,000, preferably 60,000 to 200,000. If the weight average molecular weight of the vinyl copolymer (D) is within the above range, the mechanical strength and moldability are further improved. Here, the weight average molecular weight of the vinyl copolymer (D) is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

[0067] The vinyl copolymer (D) may be used alone, or two or more kinds having different copolymer compositions and physical properties may be mixed and used.

[0068] [Other inorganic fillers] The thermoplastic resin composition of the present invention may contain other inorganic fillers other than wollastonite (B) as long as the object of the present invention is not impaired. Specific examples of the other inorganic fillers include inorganic compound powders such as talc, calcium carbonate, mica, kaolin, diatomaceous earth, silica, titania, zeolite, and glass fibers. These may be used alone or in combination of two or more. The other inorganic fillers may be those surface-treated with a silane coupling agent, a titanate coupling agent, or the like.

[0069] [Ultra-high molecular weight resin (E)] In addition to the polycarbonate resin (A), the graft copolymer (C), and the vinyl copolymer (D), the thermoplastic resin composition of the present invention may contain a high molecular weight resin (E) having a weight average molecular weight of 2 million or more, which is different from these resins. By containing the high molecular weight resin (E), the appearance of the obtained molded article and the painting appearance can be made good.

[0070] The weight average molecular weight of the high molecular weight resin (E) only needs to be 2 million or more, and the resin type and the like are not particularly limited. Preferably, it is a thermoplastic resin. For example, a (co)polymer resin containing a structural unit derived from an aromatic vinyl monomer (hereinafter referred to as "resin (E1)"), a (co)polymer resin containing a structural unit derived from a (meth)acrylic acid alkyl ester compound having 1 to 4 carbon atoms in the alkyl group (hereinafter referred to as "resin (E2)"), a (co)polymer resin of an α-olefin having 2 to 6 carbon atoms, polycarbonate, and the like can be mentioned. Among these, resin (E1) and resin (E2) are preferable.

[0071] If the weight average molecular weight of the high molecular weight resin (E) is less than 2,000,000, the effects of improving the appearance of the molded article and the painted appearance cannot be sufficiently obtained. From these viewpoints, the weight average molecular weight of the high molecular weight resin (E) is preferably 2,500,000 or more, more preferably 3,000,000 or more. On the other hand, if the weight average molecular weight of the high molecular weight resin (E) is excessively large, the thermoplastic resin composition of the present invention becomes non-uniform. Therefore, the weight average molecular weight of the high molecular weight resin (E) is preferably 7,000,000 or less, more preferably 5,000,000 or less. Here, the weight average molecular weight of the high molecular weight resin (E) can be measured by gel permeation chromatography (GPC) using standard polystyrene and dimethylformamide as a solvent.

[0072] Among the ultra-high molecular weight resins (E), examples of the aromatic vinyl monomer that forms the resin (E1) include the aromatic vinyl monomers exemplified for the graft copolymer (C). Among these, styrene and α-methylstyrene are preferable.

[0073] Further, the resin (E1) may have a structural unit derived from a polymerizable compound other than the aromatic vinyl monomer. For example, it may have a structural unit derived from a vinyl cyanide monomer, a (meth)acrylic acid ester compound, a maleimide compound, an acid anhydride, or further a vinyl monomer having a functional group such as a hydroxyl group, an amino group, an epoxy group, an amide group, a carboxyl group, an oxazoline group, etc. The other structural units can be included singly or in combination of two or more.

[0074] Regarding the above other polymerizable compounds, various vinyl monomers exemplified in the graft copolymer (C) can be mentioned. As the vinyl cyanide monomer, acrylonitrile is preferable. As the (meth)acrylic acid ester compound, methyl methacrylate and n-butyl acrylate are preferable. As the maleimide compound, N-phenylmaleimide and N-cyclohexylmaleimide are preferable. As the acid anhydride, maleic anhydride is preferable. As the hydroxyl group-containing vinyl compound, 2-hydroxyethyl methacrylate is preferred. As the epoxy group-containing vinyl compound, glycidyl methacrylate is preferred. Also, as the amide group-containing vinyl compound, acrylamide is preferred.

[0075] From the viewpoint of the moldability of the thermoplastic resin composition of the present invention, the resin (E1) is preferably a styrene copolymer containing an aromatic vinyl monomer unit and a vinyl cyanide monomer unit. This styrene copolymer may be a binary copolymer, or may be a ternary copolymer, a quaternary copolymer, etc. containing other structural units. When the resin (E1) has the following constitution, a molded product having a good balance between a good molded product appearance and heat resistance can be obtained without deteriorating the moldability.

[0076] When the resin (E1) is a binary copolymer obtained using an aromatic vinyl monomer and a vinyl cyanide monomer, the content ratios of the aromatic vinyl monomer unit and the vinyl cyanide monomer unit are preferably 50 to 95% by mass and 5 to 50% by mass, more preferably 60 to 90% by mass and 10 to 40% by mass, and still more preferably 70 to 80% by mass and 20 to 30% by mass, respectively, when the total of both is 100% by mass. If the content of the vinyl cyanide monomer unit is too large, the heat resistance of the obtained molded product may decrease and the molded product may be colored. If it is too small, the ductility may decrease.

[0077] Also, when the resin (E1) contains other structural units in addition to the aromatic vinyl monomer unit and the vinyl cyanide monomer unit, the upper limit of the amount of the polymerizable compound forming this other structural unit is preferably 50% by mass, more preferably 25% by mass, based on 100% by mass of all vinyl monomers including the aromatic vinyl monomer and the vinyl cyanide monomer. If the above usage amount exceeds 50% by mass, the processability of the thermoplastic resin composition tends to decrease. When the resin (E1) consists of an aromatic vinyl monomer unit, a vinyl cyanide monomer unit, and other structural units, the total of these structural units is preferably 55 to 90% by mass, 5 to 40% by mass, and 0 to 25% by mass, respectively, based on 100% by mass.

[0078] The resin (E2) is a (co)polymer containing a (meth)acrylic acid alkyl ester compound unit having 1 to 4 carbon atoms in the alkyl group, and is preferably polymethyl methacrylate.

[0079] The resins (E1) and (E2) can be produced in the same manner as the above-mentioned graft copolymer (C) and vinyl copolymer (D).

[0080] In the thermoplastic resin composition of the present invention, only one kind of the ultra-high molecular weight resin (E) may be used, or two or more kinds having different resin types, physical properties, etc. may be blended.

[0081] [Teflon-based resin (F)] The thermoplastic resin composition of the present invention may contain a Teflon-based resin (F) in addition to the polycarbonate resin (A), the graft copolymer (C), and the vinyl copolymer (D). By containing the Teflon-based resin (F), the appearance of the molded product and the painting appearance can be made good.

[0082] Further, the Teflon-based resin (F) may be a homopolymer PTFE consisting only of tetrafluoroethylene (TFE) units, or a modified PTFE containing TFE units and modified monomer units based on a modified monomer copolymerizable with TFE. In order to improve the dispersibility in the resin composition, as the PTFE, acrylic-modified PTFE may be used. Examples of the acrylic-modified PTFE include a resin obtained by dispersing PTFE and an acrylic resin in the same dispersion medium and then drying and modifying the solid content. By using acrylic-modified PTFE, it becomes easy to uniformly disperse PTFE in the resin composition.

[0083] The thermoplastic resin composition of the present invention may use only one type of Teflon-based resin (F), or may be blended with two or more types having different resin types, physical properties, etc.

[0084] [Content of each component] In the thermoplastic resin composition of the present invention, the content of the polycarbonate resin (A) with respect to a total of 100 parts by mass of the polycarbonate resin (A), the inorganic filler containing wollastonite (B), the graft copolymer (C), and the vinyl copolymer (D) is 45 to 65 parts by mass, the content of the inorganic filler containing wollastonite (B) is 15 to 40 parts by mass, the content of the graft copolymer (C) is 7 to 20 parts by mass, and the content of the vinyl copolymer (D) is preferably 0 to 20 parts by mass. If the content of the polycarbonate resin (A) is at least the above lower limit, high impact resistance and high heat resistance can be exhibited, and if it is at most the above upper limit, a decrease in moldability can be prevented. If the content of the inorganic filler containing wollastonite (B) is at least the above lower limit, effects such as high rigidity and low linear thermal expansion coefficient due to containing the inorganic filler can be sufficiently obtained, and if it is at most the above upper limit, deterioration of moldability and a decrease in impact resistance can be prevented. In addition, when containing other inorganic fillers other than wollastonite (B) as the inorganic filler, in order to more effectively obtain the effects of the present invention by using wollastonite (B) treated with a specific silane coupling agent, the proportion of wollastonite (B) treated with the specific silane coupling agent in 100% by mass of the inorganic filler is preferably 40% by mass or more, more preferably 60 to 100% by mass, and most preferably 100% by mass.

[0085] If the content of the graft copolymer (C) is at least the above lower limit, excellent impact resistance can be exhibited, and if it is at most the above upper limit, deterioration of moldability and molded appearance can be prevented. If the content of the vinyl copolymer (D) is at most the above upper limit, a decrease in impact resistance and heat resistance can be prevented.

[0086] When the thermoplastic resin composition of the present invention further contains an ultra-high molecular weight resin (E) or a Teflon-based resin (F), the content of the ultra-high molecular weight resin (E) or the Teflon-based resin (F) is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 8 parts by mass, still more preferably 0.5 to 5 parts by mass, based on 100 parts by mass in total of the polycarbonate resin (A), the inorganic filler containing wollastonite (B), the graft copolymer (C), and the vinyl-based copolymer (D). When the content of the ultra-high molecular weight resin (E) or the Teflon-based resin (F) is at least the above lower limit, the effect of improving the appearance of the molded article and the painting appearance by blending the ultra-high molecular weight resin (E) or the Teflon-based resin (F) can be sufficiently obtained. When the content of the ultra-high molecular weight resin (E) or the Teflon-based resin (F) is at most the above upper limit, the decrease in moldability due to excessive blending of the ultra-high molecular weight resin (E) can be prevented.

[0087] In the thermoplastic resin composition of the present invention, with respect to 100 parts by mass of the resin component corresponding to the total of the polycarbonate resin (A), the graft copolymer (C), the vinyl-based copolymer (D), and the ultra-high molecular weight resin (E), the Teflon-based resin (F), and other resins to be blended later, the content of the rubbery polymer contained derived from the graft copolymer (C) is preferably 3.5 to 20 parts by mass, particularly preferably 5 to 15 parts by weight. When the content of the rubbery polymer with respect to 100 parts by weight of the resin component is at least the above lower limit, excellent impact resistance is exhibited even in the notched impact test, and when it is at most the above upper limit, good moldability can be obtained.

[0088] [Other components] <Thermal aging inhibitor> A thermal aging inhibitor can be blended in the thermoplastic resin composition of the present invention. Examples of the thermal aging inhibitor include phenolic, phosphorus-based, sulfur-based, etc., and a mixed system selected from these 3 types is preferable. When such a mixed system is used as the thermal aging inhibitor, the effect of maintaining the tensile elongation rate when exposed to high temperature for a long time can be obtained.

[0089] Among the heat aging inhibitors, as phenolic compounds, there are 2,6-di-t-butylphenol derivatives, 2-methyl-6-t-butylphenol derivatives, octadecyl 3(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 4,4'-butylidene-bis(6-t-butyl-m-cresol), pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2[1-(2-hydroxy-3,5-di-t-pentylphenyl)-ethyl]-4,6-di-t-pentylphenyl acrylate, 2-t-butyl-6(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, and the like.

[0090] As phosphorus compounds, there are tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-t-butylphenyl phosphite), distearyl pentaerythritol diphosphite, sodium dihydrogen phosphate, disodium hydrogen phosphate, and the like.

[0091] As sulfur compounds, there are dilauryl 3,3'-thiodipropionate, dioctadecyl 3,3'-thiodipropionate, pentaerythritol-tetrakis(3-laurylpropionate), dilauryl 3,3'-thiodipropionate, and the like.

[0092] The content of the heat aging inhibitor in the thermoplastic resin composition of the present invention is usually 0 to 5% by mass, preferably 0 to 3% by mass. In the thermoplastic resin composition of the present invention, the graft copolymer (C) and the vinyl copolymer (D) other than the polycarbonate resin (A) have improved heat aging characteristics by adding a heat aging inhibitor. However, the polycarbonate resin (A) may act as a catalyst that promotes hydrolysis of the heat aging inhibitor, and there is a tendency to suppress deterioration without adding the heat aging inhibitor. In view of these opposite effects, adding the above heat aging inhibitor with an upper limit of 5% by mass can obtain an optimal heat aging prevention effect.

[0093] <Other Additives> Additives such as known weathering agents, lubricants, colorants, flame retardants, flame retardant aids, antistatic agents, and silicone oils can be incorporated into the thermoplastic resin composition of the present invention. Among these, as the weathering agent, benzotriazole-based, triazine-based, benzophenone-based, etc. are preferable. As the lubricant, ester-based lubricants such as hydrogenated castor oil are preferable. Examples of the colorant include carbon black and red iron oxide. Examples of the antistatic agent include polyethers and sulfonates having an alkyl group.

[0094] <Other resins> In the thermoplastic resin composition of the present invention, within a range not impairing the performance aimed at by the present invention, for example, in the range of 20 parts by mass or less in a total of 100 parts by mass of polycarbonate resin (A), graft copolymer (C), vinyl copolymer (D) and other resins, other thermoplastic resins other than these resins can be incorporated. Examples of the thermoplastic resin that can be incorporated into the thermoplastic resin composition of the present invention include polyolefin resins, vinyl chloride resins, acrylic resins , Po nylon resins, polyacetal resins, polyphenylene ether resins, polyarylene sulfide resins, etc. These thermoplastic resins can be used alone or in combination of two or more.

[0095] [Manufacture of Thermoplastic Resin Composition] The thermoplastic resin composition of the present invention can be produced by kneading each component using various extruders, Banbury mixers, kneaders, rolls, etc. For example, pellets of the thermoplastic resin composition of the present invention can be obtained by kneading a polycarbonate resin (A), wollastonite (B), a graft copolymer (C), a vinyl copolymer (D), and, if necessary, a ultra-high molecular weight resin (E) or a Teflon-based resin (F), and other additives. Specifically, methods such as melting the polycarbonate resin (A), wollastonite (B), graft copolymer (C), vinyl copolymer (D), and other additives used as necessary by a twin-screw extruder can be mentioned. During this melt-kneading, wollastonite (B) is preferably added by side feeding in order to efficiently exhibit high rigidity and a low linear thermal expansion coefficient. The heating temperature during this melt-kneading is appropriately selected according to the formulation of the thermoplastic resin composition, but is usually 230 to 300°C.

[0096] 〔Molded article〕 The molded article of the present invention is obtained by molding the thermoplastic resin composition of the present invention.

[0097] Examples of the molding method of the thermoplastic resin composition of the present invention include an injection molding method (including insert molding such as films and glass plates), an injection foam molding method, an injection compression molding method, an extrusion method, a blow molding method, a vacuum molding method, a pressure air molding method, a calender molding method, an inflation molding method, and the like. Among these, the injection molding method, the injection foam molding method, and the injection compression molding method are preferable because they are excellent in mass productivity and can obtain molded articles with high dimensional accuracy.

[0098] The molded article of the present invention made of the thermoplastic resin composition of the present invention can be excellent in rigidity, impact resistance, heat resistance, have a low linear thermal expansion coefficient, and furthermore, have good molding appearance and painting appearance. Therefore, it can be used as both an unpainted molded article and a painted molded article.

[0099] The molded article of the present invention can be applied to, for example, housings of personal computers (including notebook and tablet types), projectors (including liquid crystal projectors), televisions, printers, facsimiles, copiers, audio equipment, game machines, cameras (including video cameras, digital cameras, etc.), video equipment (videos, etc.), musical instruments, mobile devices (electronic notebooks, information portable terminals (PDAs), etc.), lighting equipment, communication equipment (telephones (including mobile phones, smartphones, etc.), etc.), fishing tackle, amusement equipment (pachinko articles, etc.), vehicle products, furniture products, sanitary products, building materials products, etc. Among these applications, from the viewpoint that the effects of the present invention are particularly exhibited, it is suitable as exterior parts of vehicles such as automobiles.

Examples

[0100] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples in any way as long as the gist thereof is not exceeded. In the following, "parts" means "parts by mass" and "%" means "% by mass".

[0101] [Raw materials] In the following Examples and Comparative Examples, the raw materials of the thermoplastic resin composition were resin components produced by the following methods and the following commercially available products.

[0102] [Thermoplastic resin composition] PC-1: Aromatic polycarbonate resin "Novarex 7022PJ" (viscosity average molecular weight: 21,000) manufactured by Mitsubishi Engineering Plastics Corporation PC-2: Aromatic polycarbonate resin "Novarex 7022PJ-LH1" (viscosity average molecular weight: 19,000) manufactured by Mitsubishi Engineering Plastics Corporation

[0103] [Wollastonite] Wollastonite "NYGLOS 4W" manufactured by IMERYS with an average length of 63 μm and an average diameter of 7 μm was surface-treated with various silane coupling agents and used. Table 1 below shows untreated wollastonite-1 and surface-treated wollastonite-2 to 4. Wollastonite-4 corresponds to wollastonite (B) according to the present invention.

[0104] [Table 1]

[0105] [Production of graft copolymer (C)] [Production of ABS resin (butadiene-based rubbery polymer / styrene / acrylonitrile copolymer) (ABS)] Into a stainless steel autoclave equipped with a stirring device, a heating and cooling device, a thermometer, and each raw material addition device, 80 parts by mass of ion-exchanged water, 100 parts by mass of 1,3-butadiene, 0.5 part by mass of tert-dodecyl mercaptan, 1.8 parts by mass of potassium rosinate, 0.8 part by mass of sodium carbonate, 0.075 part by mass of potassium hydroxide, and 0.15 part by mass of potassium persulfate were charged and reacted at 80°C for 24 hours to obtain an aqueous dispersion (latex) of diene-based polymer particles (hereinafter referred to as "raw material particles L1"). Laser Doppler / frequency analysis was performed using a "Microtrac UPA150 particle size analyzer" manufactured by Nikkiso Co., Ltd., and as a result of measuring the volume average particle diameter of the raw material particles L1, the volume average particle diameter of the raw material particles L1 was 300 nm. Next, into a glass flask equipped with a stirrer, in a nitrogen stream, a latex containing 60 parts by mass of the raw material particles L1, 0.2 part by mass of sodium pyrophosphate, 0.004 part by mass of ferrous sulfate heptahydrate, and 0.3 part by mass of glucose, and a solution dissolved in 8 parts by mass of ion-exchanged water were charged. With stirring, at an internal temperature of 70°C, 40 parts by mass of ion-exchanged water, 0.5 part by mass of potassium rosinate, 30 parts by mass of styrene, 10 parts by mass of acrylonitrile, 0.1 part by mass of tert-dodecyl mercaptan, and 0.25 part by mass of cumene hydroperoxide were continuously added over 3.5 hours. Then, this reaction solution was stirred for another 1 hour to obtain an aqueous dispersion (latex) of the graft copolymer (C). Thereafter, 0.5 part by mass of an antioxidant was added, and then an aqueous sulfuric acid solution was added to cause coagulation, followed by drying to obtain a powder of the graft copolymer (C). The polymerization conversion rate of the ABS resin (ABS) was 94%, the grafting rate was 51%, and the weight average molecular weight of the acetone-soluble component was 80,000.

[0106] [Production of Vinyl Copolymer (D)] [Production of <AS Resin (Styrene / Acrylonitrile Copolymer) (AS-1)>] After replacing the stainless steel autoclave equipped with ribbon blades with nitrogen, 75 parts by mass of styrene, 25 parts by mass of acrylonitrile, and 20 parts by mass of toluene were continuously added to the reaction vessel. A solution of 0.16 part by mass of tert-dodecyl mercaptan and 5 parts by mass of toluene as a molecular weight regulator, and a solution of 0.1 part by mass of 1,1'-azobis(cyclohexane-1-carbonitrile) and 5 parts by mass of toluene as a polymerization initiator were continuously supplied. The polymerization was carried out while controlling the temperature at 110°C. After the polymerization conversion rate reached 75%, the obtained copolymer solution was directly devolatilized of unreacted monomers and solvents using a twin-screw extruder with a three-stage vent to obtain an AS resin (AS-1) having a weight average molecular weight of 135,000.

[0107] [Production of <AS Resin (Styrene / Acrylonitrile Copolymer) (AS-2)>] After replacing the stainless steel autoclave equipped with ribbon blades with nitrogen, 75 parts by mass of styrene, 25 parts by mass of acrylonitrile, and 20 parts by mass of toluene were continuously added to the reaction vessel. A solution of 0.4 part by mass of tert-dodecyl mercaptan and 5 parts by mass of toluene as a molecular weight regulator, and a solution of 0.1 part by mass of 1,1'-azobis(cyclohexane-1-carbonitrile) and 5 parts by mass of toluene as a polymerization initiator were continuously supplied. The polymerization was carried out while controlling the temperature at 110°C. After the polymerization conversion rate reached 75%, the obtained copolymer solution was directly devolatilized of unreacted monomers and solvents using a twin-screw extruder with a three-stage vent to obtain an AS resin (A-2) having a weight average molecular weight of 80,000.

[0108] [Ultra-high molecular weight resin (E)] The following commercially available products were used as the ultra-high molecular weight resin (E). E-1: High molecular weight acrylic resin "Metablen (registered trademark) P-531A" manufactured by Mitsubishi Chemical Corporation (weight average molecular weight: 4.5 million) E-2: High molecular weight acrylonitrile-styrene copolymer "Blendex 869" manufactured by General Electric Specialty Chemicals (weight average molecular weight: 3.8 million)

[0109] [Teflon resin (F)] The following commercially available products were used as the Teflon resin (F). F: Acrylic-modified Teflon polymer "Metablen (registered trademark) A-3000" manufactured by Mitsubishi Chemical Corporation

[0110] [Other inorganic fillers] Talc-1: Talc with an average particle diameter of 4.75 μm (manufactured by Hayashi Kasei Co., Ltd.: Upn HS-T0.5) Talc-2: Talc with an average particle diameter of 4.5 μm (manufactured by Nippon Talc Co., Ltd.: Micro Ace P-4) treated with 3-glycidoxypropyltriethoxysilane GF-1: Glass fiber with an average fiber length of 40 μm and an average fiber diameter of 11 μm (manufactured by Nitto Boseki Co., Ltd.: PF 40E-001) GF-2: Epoxysilane-treated glass fiber with an average fiber length of 3 mm and an average fiber diameter of 13 μm (manufactured by Nitto Boseki Co., Ltd. CS 3PE 937S)

[0111] [Examples 1 to 12, Comparative Examples 1 to 9] Of the raw materials shown in Tables 2 and 3, excluding the inorganic filler, the raw materials were blended at the ratios shown in Tables 2 and 3, and after blending these with a Henschel mixer, they were extruded at 260 °C using a vented twin-screw extruder TEM26SS manufactured by Shibaura Machine Co., Ltd. The addition amount of the inorganic filler was controlled with a gravimetric feeder so as to be at the ratios shown in Tables 2 and 3, and it was added by side feeding to obtain pellets of the thermoplastic resin composition. The obtained resin pellets were dried at 120 °C for about 5 hours to make the moisture content in the pellets 200 ppm or less, and then, using an injection molding machine (manufactured by Shibaura Machine Co., Ltd.: IS-100GN), dumbbell-shaped (ISO3167: test piece A shape) test pieces were continuously injection molded under the conditions of a cylinder temperature of 260 °C, a mold temperature of 70 °C, a molding cycle of 50 seconds, and an injection speed of 40 mm / sec. Also, as test pieces for molding appearance evaluation and painting appearance evaluation, 150 × 150 × 3 mm plate test pieces were continuously injection molded using an injection molding machine (manufactured by Shibaura Machine Co., Ltd.: EC130SX) under the conditions of a cylinder temperature of 260 °C, a mold temperature of 80 °C, a molding cycle of 50 seconds, and an injection speed of 50 mm / sec. The test pieces left standing for 24 hours in an environment of a temperature of 23 °C and a relative humidity of 50% were used as test pieces, and the following evaluations were carried out, and the results are shown in Tables 2 and 3. In addition, in Tables 2 and 3, the content of the rubbery polymer derived from the ABS resin in 100 parts by mass of the resin component was also noted.

[0112] <Charpy impact strength> In accordance with ISO 179-1: 2013 annual edition, the Charpy impact strength was measured. This value is preferably 20 kJ / m 2 or more.

[0113] <Flexural modulus> In accordance with ISO 178: 2013 annual edition, the flexural modulus was measured. The flexural modulus is an index of the rigidity of the molded product. This value is preferably 4000 MPa or more.

[0114] <Linear thermal expansion coefficient> The dumbbell test piece was cut from the center in the resin flow direction (MD direction) to a length of 10 mm to obtain a measurement sample. Using a TMA SS7100 device manufactured by Hitachi High-Tech Sciences Corporation, in compression mode, with a load of 5 g, under a nitrogen atmosphere, the temperature was raised from room temperature to 100 °C at 5 °C / min., then cooled to 25 °C at 5 °C / min., and then heated again from 25 °C to 100 °C at 5 °C / min. At this time, the average linear thermal expansion rate between 30 °C and 70 °C during the second heating was measured. This value is preferably 5×10 -5 / K or less.

[0115] <Appearance of molded product> The appearance of the obtained plate test piece was visually observed and evaluated according to the following evaluation criteria. ○: The surface is smooth and has no defects. ×: There are defects such as a foreign body feeling or flow marks on the surface.

[0116] <Appearance of coating> Coating was performed on the obtained plate test piece according to the following procedure, and the appearance of the coating on its surface was visually observed and evaluated according to the following criteria. (1) Coating Spray coating (coating film thickness: 20 - 30 μm) of a coating paint composed of 80 parts by mass of a urethane-based paint main agent, 40 parts by mass of a thinner for synthetic resin paint, and 20 parts by mass of a curing agent was performed on the surface of the plate test piece, and it was left standing at 23 °C for 5 minutes. (2) Drying Thereafter, it was dried at 80 °C for 30 minutes to obtain a coated test piece. <Evaluation criteria for appearance of coating> ○: There is no coating unevenness and it is good. ×: There is coating unevenness.

[0117] <Heat resistance (HDT)> In accordance with ISO 75-2:2013 Edition, the deflection temperature by the 1.80 MPa load flatwise method was measured. This value is preferably 100 °C or higher.

[0118] <Melt volume rate (MVR)> In accordance with the ISO 1133 standard, the MVR of the pellets was measured under the conditions of 260 °C - 98 N. Note that MVR serves as an indicator of the moldability of the thermoplastic resin composition.

[0119]

Table 2

[0120]

Table 3

[0121] It can be seen from Tables 2 and 3 that the following is true. In Comparative Example 1 without the addition of an inorganic filler, the impact resistance is high, but the rigidity is low and the linear thermal expansion coefficient is also high. In Comparative Example 2 using untreated wollastonite, and Comparative Examples 3 and 4 using wollastonite treated with other treatment agents, the rigidity was improved and the linear thermal expansion coefficient was also reduced, but the impact resistance was significantly decreased. In Comparative Examples 5 to 9 using talc or glass fiber other than wollastonite, the decrease in impact resistance was also large. Also, Comparative Example 1 without the addition of an inorganic filler is excellent in molding appearance and painting appearance, but Comparative Examples 2 to 9 are all inferior in molding appearance and painting appearance.

[0122] On the other hand, in Examples 1 to 12 using wollastonite treated with hexadecylsilane, the decrease in impact resistance was suppressed, the rigidity was increased, and the linear thermal expansion coefficient was also reduced. In particular, in Examples 1, 3 to 5, and 8 to 12 containing the ultra-high molecular weight resin (E) or the Teflon-based resin (F), the molding appearance and painting appearance are also good.

[0123] From these results, it can be seen that according to the present invention, it is possible to provide a thermoplastic resin molded product that well balances the required characteristics of high rigidity, high impact resistance, high heat resistance, low linear thermal expansion coefficient, and furthermore, good molding appearance and good painting appearance in a high dimension.

Claims

1. A thermoplastic resin composition comprising a polycarbonate resin (A), wollastonite (B), and a graft copolymer (C) obtained by polymerizing at least an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of a rubber polymer, further comprising an ultra-high molecular weight resin (E) different from the polycarbonate resin (A) and the graft copolymer (C) and having a weight average molecular weight of 2 million or more, or a Teflon resin (F), and further comprising a vinyl copolymer (D) different from the ultra-high molecular weight resin (E) and obtained by copolymerizing at least an aromatic vinyl monomer and a vinyl cyanide monomer, A thermoplastic resin composition comprising 45 to 65 parts by mass of polycarbonate resin (A), 15 to 40 parts by mass of inorganic filler containing wollastonite (B), 7 to 20 parts by mass of graft copolymer (C), 20 parts by mass or less of vinyl copolymer (D), and 0.1 to 10 parts by mass of ultra-high molecular weight resin (E) or Teflon-based resin (F), relative to a total of 100 parts by mass of polycarbonate resin (A), inorganic filler containing wollastonite (B), graft copolymer (C), and vinyl-based copolymer (D), A thermoplastic resin composition (excluding thermoplastic resin compositions containing polyester resins) characterized in that wollastonite (B) is treated with a silane coupling agent containing a linear alkyl group having 12 or more carbon atoms.

2. The thermoplastic resin composition according to claim 1, wherein the graft copolymer (C) is a rubber-reinforced styrene-acrylonitrile graft copolymer obtained by graft polymerizing a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of a diene rubber polymer.

3. A molded article obtained by molding the thermoplastic resin composition according to claim 1 or 2.

4. 4. The molded article according to claim 3, which is an exterior vehicle part.

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