Styrene-based resin composition and molded article

Abstract

The present invention provides a styrene-based resin composition that can produce molded articles having excellent mechanical properties, and a molded article using the same. [Solution] A styrene resin composition comprising a resin (A) containing a styrene resin (A1) and a polyamide (A2) having a syndiotactic structure, and a compatibilizer (B), wherein the polyamide (A2) comprises a component unit (A2a) derived from a dicarboxylic acid and a component unit (A2b) derived from a diamine, and the polyamide (A2) has a polyamide 6T structure in which a component unit (A2a) derived from terephthalic acid and a component unit (A2b) derived from 1,6-diaminohexane are adjacent, and the mass ratio of the polyamide (A2) to the styrene resin (A1) [(A2) / (A1)] is 55 / 45 to 95 / 5.

Description

[Technical Field]

[0001] The present invention relates to styrene-based resin compositions and molded articles. [Background technology]

[0002] Styrene-based resins with a syndiotactic structure (syndiotactic polystyrene; hereinafter also referred to as SPS) possess excellent properties such as mechanical strength, heat resistance, electrical properties, water absorption dimensional stability, and chemical resistance. Therefore, SPS is extremely useful as a resin used in a wide range of applications, including electrical and electronic equipment materials, automotive parts, home appliance parts, various machine parts, and industrial materials. To balance the properties of SPS, such as mechanical strength, toughness, heat resistance, chemical resistance, and moldability, blending with other resins is being considered, and resins mixed with polyamide resins are also being explored.

[0003] For example, Patent Document 1 discloses a styrene resin composition and a molded article thereof that contains a polyamide-6,6 and polyamide-6 as essential components, a styrene resin having a syndiotactic structure, a polar group-modified polyphenylene ether, and a rubbery elastic body, and that exhibits excellent dimensional accuracy, surface appearance, heat resistance, and solvent resistance. Furthermore, Patent Document 2 discloses a heat-resistant resin composition comprising a predetermined resin consisting of an aromatic polyamide resin and syndiotactic polystyrene, an acid-modified polyphenylene ether and an inorganic filler, wherein the resin comprises a dicarboxylic acid component containing terephthalic acid in a predetermined proportion and a diamine component containing 1,9-nonanediamine and / or 2-methyl-1,8-octanediamine in a predetermined proportion, and it is possible to obtain a heat-resistant resin composition and a molded article thereof that has sufficient heat resistance to handle lead-free reflow soldering processes and excellent water resistance and mechanical properties. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-213125 [Patent Document 2] Japanese Patent Publication No. 2013-14711 [Overview of the project] [Problems that the invention aims to solve]

[0005] By further improving the mechanical properties of such styrene-based resin compositions, such as tensile strength and impact resistance, they can be more suitably used in the above-mentioned applications (especially in the fields of electrical and electronic equipment, automobiles, etc.).

[0006] Therefore, the object of the present invention is to provide a styrene-based resin composition that can produce a molded article having excellent mechanical properties, and a molded article using the same. [Means for solving the problem]

[0007] As a result of diligent research, the inventors have found that a styrene-based resin composition containing SPS and polyamide, using a specific polyamide and containing SPS and polyamide in a specific ratio, solves the aforementioned problems. That is, the present invention relates to the following [1] to

[15] .

[0008] [1] A styrene resin composition comprising a resin (A) containing a styrene resin (A1) and a polyamide (A2) having a syndiotactic structure, and a compatibilizer (B) having polar groups that are compatible with the styrene resin (A1) and reactable with the polyamide (A2), The polyamide (A2) comprises a component unit (A2a) derived from a dicarboxylic acid and a component unit (A2b) derived from a diamine. The polyamide (A2) has a polyamide 6T structure in which a component unit (A2a) derived from terephthalic acid and a component unit (A2b) derived from 1,6-diaminohexane are adjacent to each other. A styrene-based resin composition in which the mass ratio of the polyamide (A2) to the styrene-based resin (A1) [(A2) / (A1)] is 55 / 45 to 95 / 5. [2] The styrene-based resin composition according to [1], further comprising, as a component unit (A2a) derived from the dicarboxylic acid, at least one selected from the group consisting of a component unit derived from isophthalic acid and a component unit derived from adipic acid. [3] The styrene-based resin composition according to [1] or [2], wherein the polyamide (A2) comprises the polyamide 6T structure as a main component. [4] The styrene-based resin composition according to any one of [1] to [3], wherein the melting point of the polyamide (A2) is 300°C or higher and 340°C or lower. [5] The styrene resin composition according to any one of [1] to [4], wherein the total content of the polyamide (A2) and the styrene resin (A1) is 30% by mass or more and 99% by mass or less in the styrene resin composition. [6] The styrene-based resin composition according to any one of [1] to [5], wherein the compatibilizer (B) is one or more selected from the group consisting of modified polyphenylene ether and modified polystyrene. [7] The styrene-based resin composition according to any one of [1] to [6], wherein the content of the compatibilizer (B) is 1% by mass or more and 5% by mass or less in the styrene-based resin composition. [8] Furthermore, a styrene-based resin composition according to any one of [1] to [7], comprising an inorganic filler (C). [9] The styrene-based resin composition according to [8], wherein the inorganic filler (C) is a glass filler.

[10] The styrene-based resin composition according to [8] or [9], wherein the content of the inorganic filler (C) is 10% by mass or more and 40% by mass or less in the styrene-based resin composition.

[11] Furthermore, a styrene-based resin composition according to any one of [1] to

[10] , comprising an antioxidant (D).

[12] The styrene-based resin composition according to

[11] , wherein the content of the antioxidant (D) is 0.1% by mass or more and 3% by mass or less in the styrene-based resin composition.

[13] The styrene-based resin composition according to any one of [1] to

[12] , wherein the melt flow rate (MFR) of the styrene-based resin composition at 330°C is 2 g / 10 min or more and 30 g / 10 min or less. A molded article containing any one of the styrene-based resin compositions described in

[14] [1] to

[13] .

[15] The molded article according to

[14] , wherein the tensile breaking strength is 170 MPa or more. [Effects of the Invention]

[0009] The present invention provides a styrene-based resin composition that contains SPS and polyamide, and by using a specific polyamide and including SPS and polyamide in a specific ratio, it is possible to obtain a molded article having excellent mechanical properties, as well as a molded article using the same. [Modes for carrying out the invention]

[0010] <Resin composition> The styrene-based resin composition of this embodiment is a styrene-based resin composition comprising a resin (A) containing a styrene-based resin (A1) and a polyamide (A2) having a syndiotactic structure, and a compatibilizer (B) having polar groups that are compatible with the styrene-based resin (A1) and reactable with the polyamide (A2). In this styrene-based resin composition, polyamide (A2) contains component units (A2a) derived from dicarboxylic acid and component units (A2b) derived from diamine, and has a polyamide 6T structure in which component units (A2a) derived from terephthalic acid and component units (A2b) derived from 1,6-diaminohexane are adjacent. Furthermore, in this styrene-based resin composition, the mass ratio of polyamide (A2) to styrene-based resin (A1) [(A2) / (A1)] is 55 / 45 to 95 / 5. The following describes in detail each component that makes up the resin composition.

[0011] [Resin (A)] The resin (A) contained in the styrene resin composition of the present embodiment includes a styrene resin (SPS) (A1) having a syndiotactic structure and a specific polyamide (A2), and the mass ratio [(A2) / (A1)] of the polyamide (A2) to the styrene resin (A1) is 55 / 45 to 95 / 5.

[0012] 〔Styrene resin (A1) having a syndiotactic structure〕 The styrene resin (A1) is an SPS having a highly syndiotactic structure. By blending SPS, the molded body can have various properties such as the above-mentioned mechanical strength, and the water absorption rate can be reduced. In the present specification, "syndiotactic" means that the phenyl rings in adjacent styrene units are alternately arranged (hereinafter referred to as syndiotacticity) with respect to the plane formed by the main chain of the polymer block at a high ratio. Tacticity can be quantitatively identified by nuclear magnetic resonance method using isotopic carbon ( 13 13C-NMR method). 13 By the 13C-NMR method, the abundance ratios of a plurality of consecutive constitutional units, for example, two consecutive monomer units as a dyad, three monomer units as a triad, and five monomer units as a pentad can be quantified.

[0013] In the present embodiment, the "styrene resin having a highly syndiotactic structure" means a styrene polymer such as polystyrene, poly(hydrocarbon-substituted styrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinyl benzoate), etc. having a syndiotacticity of usually 75 mol% or more, preferably 85 mol% or more in racemic dyad (r), or usually 30 mol% or more, preferably 50 mol% or more in racemic pentad (rrrr), a hydrogenated polymer or mixture thereof, or a copolymer having these as a main component.

[0014] Examples of poly(hydrocarbon-substituted styrene) include poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tert-butylstyrene), poly(phenylstyrene), poly(vinylnaphthalene), and poly(vinylstyrene). Examples of poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), and poly(fluorostyrene), and examples of poly(halogenated alkylstyrene) include poly(chloromethylstyrene). Examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene).

[0015] Examples of comonomer components of copolymers containing the aforementioned structural units include, in addition to the monomers of the styrene polymer, olefin monomers such as ethylene, propylene, butene, hexene, and octene; diene monomers such as butadiene and isoprene; and polar vinyl monomers such as cyclic olefin monomers, cyclic diene monomers, methyl methacrylate, maleic anhydride, and acrylonitrile. Suitable copolymers for the styrene-based resin (A1) include copolymers of styrene and p-methylstyrene, copolymers of styrene and p-tert-butylstyrene, and copolymers of styrene and divinylbenzene, with copolymers of styrene and p-methylstyrene being preferred.

[0016] Among the styrene-based resins, one or more selected from polystyrene, poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(m-chlorostyrene), poly(p-fluorostyrene), and copolymers of styrene and p-methylstyrene are preferred, one or more selected from polystyrene, poly(p-methylstyrene), poly(m-methylstyrene), and copolymers of styrene and p-methylstyrene are more preferred, and copolymers of polystyrene and styrene and p-methylstyrene are even more preferred.

[0017] SPS(A1) has a weight-average molecular weight of preferably 1 × 10⁶, from the viewpoint of improving the fluidity of the resin during molding and the mechanical properties of the resulting molded article. 4 The above 1 x 10 6 More preferably, the weight-average molecular weight is 50,000 to 500,000. 4 If the above is true, a molded product with sufficient strength can be obtained. On the other hand, if the weight-average molecular weight is 1 × 10 6 The following conditions ensure that there are no problems with the fluidity of the resin during molding. In this specification, unless otherwise specified, the weight-average molecular weight is the value obtained by gel permeation chromatography at 145°C using a GPC instrument (HLC-8321GPC / HT) and a GPC column (GMHHR-H(S)HTC / HT) manufactured by Tosoh Corporation, with 1,2,4-trichlorobenzene as the eluent, and converted using a calibration curve for standard polystyrene.

[0018] When the melt flow rate (MFR) of SPS(A1) is measured under conditions of a temperature of 300°C and a load of 1.2 kg, it is preferably 2.0 g / 10 min or more, more preferably 4.0 g / 10 min or more, preferably 50 g / 10 min or less, and more preferably 30 g / 10 min or less. If the MFR value of SPS(A1) is 2.0 g / 10 min or more, there are no problems with fluidity during molding, and if it is 50 g / 10 min or less, preferably 30 g / 10 min or less, a molded product with sufficient mechanical properties can be obtained.

[0019] SPS(A1) can be produced, for example, by polymerizing a styrene monomer (a monomer corresponding to the styrene polymer) using a titanium compound and a condensation product of water and trialkylaluminum (aluminoxane) as catalysts in an inert hydrocarbon solvent or in the absence of a solvent (see, for example, Japanese Patent Application Publication No. 2009-068022).

[0020] [Polyamide (A2)] The polyamide (A2) constituting the styrene-based resin composition of this embodiment contains a component unit (A2a) derived from a dicarboxylic acid and a component unit (A2b) derived from a diamine, and has a polyamide 6T structure in which a component unit derived from terephthalic acid is adjacent to the component unit derived from the dicarboxylic acid (A2a) and a component unit derived from 1,6-diaminohexane is adjacent to the component unit derived from the diamine (A2b).

[0021] (Component unit derived from dicarboxylic acid (A2a)) The component unit (A2a) derived from dicarboxylic acid includes the component unit derived from terephthalic acid, as described above.

[0022] The component unit (A2a) derived from a dicarboxylic acid may include component units derived from other dicarboxylic acids. Examples of other dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Of these, aliphatic dicarboxylic acids and aromatic dicarboxylic acids other than terephthalic acid are preferred.

[0023] Examples of the above-mentioned aliphatic dicarboxylic acid include aliphatic dicarboxylic acids having 4 to 20 carbon atoms. Preferably, the number of carbon atoms is 5 to 10. Examples of such aliphatic dicarboxylic acids include adipic acid, azelaic acid, and sebacic acid, with adipic acid being preferred.

[0024] Examples of the above-mentioned alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid and its esters.

[0025] Aromatic dicarboxylic acids other than terephthalic acid mentioned above include isophthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid, and others, with isophthalic acid being preferred.

[0026] (Component unit (A2b) derived from diamine) The component unit (A2b) derived from diamine includes the component unit derived from 1,6-diaminohexane, as described above.

[0027] The component unit (A2b) derived from the diamine may include component units derived from other diamines. Examples of other diamines include aliphatic diamines other than 1,6-diaminohexane, alicyclic diamines having 4 to 20 carbon atoms, and aromatic diamines.

[0028] Examples of aliphatic diamines other than 1,6-diaminohexane include aliphatic diamines having 4 to 12 carbon atoms, preferably 5 to 10 carbon atoms. These aliphatic diamines include linear alkylenediamines and branched alkylenediamines. Examples of linear alkylenediamines include 1,4-diaminobutane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane. The formulation may contain only one linear alkylenediamine or two or more. Examples of branched alkylenediamines include 2,2-dimethyldiaminopropane, 1,1-dimethyl-1,4-diaminobutane, 2-methyl-1,5-diaminopentane, 2,5-dimethyl-1,6-diaminohexane, 2,3-dimethyl-1,7-diaminoheptane, 2-methyl-1,8-diaminooctane, and 5-methyl-1,9-diaminononane. Among these, 2-methyl-1,8-diaminooctane is preferred.

[0029] Examples of the above-mentioned alicyclic diamines having 4 to 20 carbon atoms include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, and 2,6-bisaminomethylnorbornane. Examples of the above-mentioned aromatic diamines include metaxylylenediamine.

[0030] The polyamide (A2) used in this embodiment has a polyamide structure obtained by the reaction of a dicarboxylic acid and a diamine, and as described above, it contains a component unit (A2a) derived from terephthalic acid and a component unit (A2b) derived from 1,6-diaminohexane, and has a polyamide 6T structure in which these component units (A2a) and (A2b) are adjacent to each other. The polyamide (A2) preferably contains the polyamide 6T structure as its main component. Here, "main component" means the polyamide structure that is present in the largest quantity among all the polyamide structures that make up the polyamide (A2). More specifically, the content of the polyamide 6T structure in the polyamide (A2) is preferably 30 mol% to 99 mol% of all the polyamide structures contained in the polyamide (A2).

[0031] This polyamide (A2) may include not only the polyamide 6T structure but also the component units (A2a) and (A2b) exemplified above, and therefore may contain various polyamide structures. Examples of such polyamide structures include aliphatic polyamide structures and aromatic polyamide structures. Aliphatic polyamide structures are obtained by polymerizing an aliphatic diamine component and an aliphatic dicarboxylic acid component. Specifically, examples include polyamide 4, polyamide 6, polyamide 66, polyamide 34, polyamide 12, polyamide 11, and polyamide 610 structures, with polyamide 6 and polyamide 66 structures being preferred, and polyamide 66 structures being more preferred. Aromatic polyamide structures are obtained by polymerizing aliphatic diamines and aromatic dicarboxylic acids. Specifically, examples include polyamide 6I structures, polyamide 9T structures, and polyamide 9I structures, with polyamide 6I structures being preferred. Here, the polyamide 6I structure is a polyamide structure in which component units derived from 1,6-diaminohexane and component units derived from isophthalic acid are adjacent; the polyamide 9T structure is a polyamide structure in which component units derived from 1,9-nonanediamine and / or 2-methyl-1,8-octanediamine and component units derived from terephthalic acid are adjacent; and the polyamide 9I structure is a polyamide structure in which component units derived from 1,9-nonanediamine and / or 2-methyl-1,8-octanediamine and component units derived from isophthalic acid are adjacent.

[0032] Polyamide (A2) may contain both the aliphatic polyamide structure and the aromatic polyamide structure in addition to the polyamide 6T structure. For example, it may contain the polyamide 6T structure, the polyamide 6I structure, and the polyamide 66 structure. By including the polyamide 6I structure and the polyamide 66 structure in addition to the polyamide 6T structure, the melting point of polyamide (A2) can be lowered, thereby reducing the melting point of the styrene-based resin composition and improving the resin fluidity during molding.

[0033] The melting point of polyamide (A2) is preferably 300°C to 340°C, more preferably 305°C to 330°C, and even more preferably 310°C to 320°C, from the viewpoint of balancing high heat resistance and moldability.

[0034] Furthermore, the mass ratio of polyamide (A2) to styrene-based resin (A1) in resin (A) [(A2) / (A1)] is between 55 / 45 and 95 / 5. When this mass ratio is 55 / 45 or higher, the mechanical properties of the molded article can be improved, and in particular, a good balance can be achieved in tensile breaking strength, tensile breaking strain, tensile modulus, Charpy impact strength, and flexural strength. Also, when the mass ratio [(A2) / (A1)] in resin (A) is 95 / 5 or lower, the water absorption rate of the molded article can be reduced. The mass ratio [(A2) / (A1)] of styrene-based resin (A1) to polyamide (A2) in resin (A) is preferably 60 / 40 to 93 / 7, more preferably 65 / 35 to 91 / 9, and even more preferably 70 / 30 to 90 / 10, from the viewpoint of improving the mechanical properties of the molded article and reducing the water absorption rate.

[0035] Here, the reason why the mechanical properties of the molded article can be improved by setting the mass ratio of polyamide (A2) to styrene-based resin (A1) in resin (A) within the above range [(A2) / (A1)] is not entirely clear. However, it is thought that the SPS and the polyamide having a specific structure (polyamide 6T structure), in combination with the compatibilizer (B) described below, reach an optimal state of compatibility, thereby improving and improving the mechanical properties. Furthermore, this is further improved by including the inorganic filler (C) described below, as the bonding between the inorganic filler (C) and other resin components at the interface between them becomes better, making it less likely for fracture to occur starting from the interface.

[0036] The content of resin (A) in this embodiment (total content of styrene-based resin (A1) and polyamide (A2)) is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more in the styrene-based resin composition, and also preferably 99% by mass or less, more preferably 85% by mass or less, even more preferably 75% by mass or less, and even more preferably 70% by mass or less in the styrene-based resin composition. From the same viewpoint as above, the content of resin (A) is preferably 30% by mass or more and 99% by mass or less, more preferably 40% by mass or more and 85% by mass or less, even more preferably 50% by mass or more and 75% by mass or less, and even more preferably 65% ​​by mass or more and 70% by mass or less in the styrene-based resin composition.

[0037] [Compatibilizer (B)] The styrene-based resin composition of this embodiment preferably contains a compatibilizer (B) which is compatible with the styrene-based resin (A1) and has polar groups that can react with the polyamide (A2). Compatibilizer (B) is a component added with the aim of improving the compatibility between SPS (A1) and polyamide (A2), finely dispersing the domains, and improving the interfacial strength between each component.

[0038] The compatibilizer (B) is compatible with SPS (A1), and a structure that contributes to compatibility is preferably one that contains a chain compatible with SPS within the polymer chain. Examples of such structures include those in which polystyrene, polyphenylene ether, polyvinyl methyl ether, etc., are present as the main chain or graft chain of the polymer chain, with polyphenylene ether being preferred. In other words, the compatibilizer (B) preferably has one or more selected from polystyrene, polyphenylene ether, and polyvinyl methyl ether as the main chain or graft chain of the polymer chain, and more preferably has polyphenylene ether as the main chain or graft chain of the polymer chain. A polar group that can react with polyamide (A2) refers to a functional group that can react with the polar groups of the polyamide. Preferred examples of such functional groups include one or more selected from the group consisting of acid anhydride groups, carboxylic acid groups, carboxylic acid ester groups, carboxylic acid halide groups, carboxylic acid amide groups, carboxylic acid bases, sulfonic acid groups, sulfonic acid ester groups, sulfonate chloride groups, sulfonic acid amide groups, sulfonic acid bases, epoxy groups, amino groups, imide groups, and oxazoline groups, with at least one selected from the group consisting of acid anhydride groups and carboxylic acid groups being more preferred.

[0039] The compatibilizer (B) is one or more selected from the group consisting of modified polyphenylene ether and modified polystyrene, with modified polyphenylene ether being preferred. Examples of modified polyphenylene ethers include fumaric acid-modified polyphenylene ether, maleic anhydride-modified polyphenylene ether, (styrene-maleic anhydride)-polyphenylene ether-graft polymer, glycidyl methacrylate-modified polyphenylene ether, and amine-modified polyphenylene ether. Preferably, fumaric acid-modified polyphenylene ether and maleic anhydride-modified polyphenylene ether are preferred, and more preferably, fumaric acid-modified polyphenylene ether.

[0040] The modified polyphenylene ether can be obtained by modifying a known polyphenylene ether using a modifying agent, but is not limited to this method as long as it is usable for the purposes of the present invention. The polyphenylene ether is a known compound, and for this purpose, refer to U.S. Patents 3,306,874, 3,306,875, 3,257,357 and 3,257,358. The polyphenylene ether is usually prepared by an oxidative coupling reaction using a disubstituted or trisubstituted phenol in the presence of a copper amine complex catalyst. The copper amine complex can be a copper amine complex derived from primary, secondary, and tertiary amines.

[0041] Examples of polyphenylene ethers include poly(2,6-dimethyl-1,4-phenylene ether), poly(2,3-dimethyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-chloromethyl-1,4-phenylene ether), poly(2-methyl-6-hydroxyethyl-1,4-phenylene ether), poly(2-methyl-6-n-butyl-1,4-phenylene ether), poly(2-ethyl-6-isopropyl-1,4-phenylene ether), poly(2-ethyl-6-n-propyl-1,4-phenylene ether), poly(2,3,6-trimethyl-1,4-phenylene ether), poly[2-(4'-methylphenyl)-1,4-phenylene ether], poly(2-bromo-6-phenyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2- Poly(phenyl-1,4-phenylene ether), poly(2-chloro-1,4-phenylene ether), poly(2-methyl-1,4-phenylene ether), poly(2-chloro-6-ethyl-1,4-phenylene ether), poly(2-chloro-6-bromo-1,4-phenylene ether), poly(2,6-di-n-propyl-1,4-phenylene ether), poly(2-methyl-6-isopropyl-1,4-phenylene ether) Examples include poly(2-chloro-6-methyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2,6-dibromo-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenylene ether), poly(2,6-diethyl-1,4-phenylene ether), and poly(2,6-dimethyl-1,4-phenylene ether), with poly(2,6-dimethyl-1,4-phenylene ether) being preferred.

[0042] Copolymers derived from two or more phenolic compounds used in the preparation of the polyphenylene ether, and copolymers of polyphenylene ether with vinyl aromatic compounds such as polystyrene can also be used.

[0043] Modifying agents used to modify polyphenylene ethers include compounds having both an ethylenic double bond and a polar group within the same molecule. Specifically, examples include maleic anhydride, maleic acid, fumaric acid, maleic acid esters, fumaric acid esters, maleimide and its N-substituted derivatives, maleate salts, fumarate salts, acrylic acid, acrylic acid esters, acrylamide, acrylicate salts, methacrylic acid, methacrylic acid esters, methacrylamide, methacrylate salts, and glycidyl methacrylate. Of these, maleic anhydride, fumaric acid, and glycidyl methacrylate are particularly preferred. The above-mentioned modifying agents may be used individually or in combination of two or more.

[0044] Modified polyphenylene ether can be obtained, for example, by reacting the polyphenylene ether with a modifying agent in the presence of a solvent or other resin. There are no particular restrictions on the modification method, and known methods can be used. Specifically, methods include melt-kneading the reaction at a temperature in the range of 150 to 350°C using a roll mill, Banbury mixer, extruder, etc., and heating the reaction in a solvent such as benzene, toluene, or xylene. Furthermore, to facilitate the reaction, it is also effective to include radical generating agents such as benzoyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl peroxybenzoate, azobisisobutyronitrile, azobisisovaleronitrile, or 2,3-diphenyl-2,3-dimethylbutane in the reaction system. As for the modification method, melt-kneading in the presence of a radical generating agent is preferred.

[0045] Examples of modified polystyrenes include styrene-maleic anhydride copolymers, styrene-glycidyl methacrylate copolymers, terminally carboxylic acid-modified polystyrenes, terminally epoxy-modified polystyrenes, terminally oxazoline-modified polystyrenes, terminally amine-modified polystyrenes, sulfonated polystyrenes, styrene-based ionomers, styrene-methyl methacrylate-graft polymers, (styrene-glycidyl methacrylate)-methyl methacrylate-graft copolymers, acid-modified acrylic-styrene-graft polymers, (styrene-glycidyl methacrylate)-styrene-graft polymers, and polybutylene terephthalate-polystyrene-graft polymers. Furthermore, the (modified) polystyrene in this compatibilizer (B) does not contain the aforementioned SPS(A1).

[0046] From the viewpoint of improving the mechanical properties of the molded article, the content of the compatibilizer (B) in the styrene resin composition is preferably 1% by mass or more, more preferably 1.5% by mass or more, even more preferably 2% by mass or more, and also preferably 5% by mass or less, more preferably 4.5% by mass or less, and even more preferably 4% by mass or less.

[0047] [Inorganic filler (C)] The styrene-based resin composition of this embodiment preferably further contains an inorganic filler (C). By including an inorganic filler (C), the strength and elastic modulus of the molded article can be improved. The shape of the inorganic filler (C) is not particularly limited, and known inorganic fillers can be used, such as fibrous, spherical, plate-like, or flaky forms. Examples of fibrous fillers include glass fibers, carbon fibers, whiskers, ceramic fibers, and metal fibers, with glass fibers being preferred. Examples of whiskers include boron, alumina, silica, and silicon carbide. Examples of ceramic fibers include gypsum, potassium titanate, magnesium sulfate, and magnesium oxide. Examples of metal fibers include copper, aluminum, and steel. Inorganic fillers can take the form of cloth, mat, condensed cut, short fibers, filaments, or whiskers. In the case of condensed cut, the length is preferably 0.05 to 50 mm, and the fiber diameter is preferably 5 to 20 μm. In the case of cloth or mat, the length is preferably 1 mm or more, and more preferably 5 mm or more.

[0048] Examples of spherical, plate-shaped, and flaky fillers include talc, carbon black, graphite, titanium dioxide, silica, mica, calcium carbonate, calcium sulfate, barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, oxysulfate, tin oxide, alumina, kaolin, silicon carbide, metal powder, glass powder, glass flakes, and glass beads, with glass powder, glass flakes, and glass beads being preferred.

[0049] The inorganic filler (C) is preferably a glass filler. The glass filler is more preferably one or more selected from glass fibers, glass powder, glass flakes, milled fibers, glass cloth, and glass beads, and glass fibers are even more preferred because they provide excellent mechanical strength. Examples of glass fillers include E glass, C glass, S glass, D glass, ECR glass, A glass, AR glass, etc. Glass that does not contain boron oxide can also be used.

[0050] The glass fibers are preferably 0.05 to 50 mm in length and 5 to 20 μm in diameter.

[0051] In order to improve adhesion with SPS(A1), the inorganic filler (C) is preferably surface-treated with a coupling agent, more preferably with a silane-based coupling agent or a titanium-based coupling agent, and even more preferably with a silane-based coupling agent from the viewpoint of improving compatibility with the resin component.

[0052] Specific examples of silane coupling agents include triethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(1,1-epoxycyclohexyl)ethyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and γ-mercaptopropyltrimeth Examples include xysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyl-tris(2-methoxyethoxy)silane, N-methyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-4,5-dihydroimidazolepropyltriethoxysilane, hexamethyldisilazane, N,N-bis(trimethylsilyl)urea, and 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine. Among these, aminosilanes and epoxysilanes such as γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane are preferred.

[0053] Specific examples of titanium-based coupling agents include isopropyltriisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropyltris(dioctyl pyrophosphate) titanate, tetraisopropylbis(dioctyl phosphite) titanate, tetraoctylbis(ditridecyl phosphite) titanate, tetra(1,1-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, and bis(dioctyl pyrophosphate)oxyacetate. Examples include titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tri(N-amidoethyl,aminoethyl) titanate, dicumylphenyl oxyacetate titanate, and diisostearoylethylene titanate. Among these, isopropyl tri(N-amidoethyl,aminoethyl) titanate is preferred.

[0054] Surface treatment of the inorganic filler using the coupling agent can be carried out by conventional known methods. Examples include sizing treatment by applying an organic solvent solution or suspension of the coupling agent, dry mixing treatment, spray method, integral blend method, and dry concentrate method, with sizing treatment, dry mixing treatment, and spray method being preferred.

[0055] The inorganic filler (C) content is preferably 1% by mass or more and 50% by mass or less in the styrene-based resin composition. If the amount of inorganic filler (C) is 1% by mass or more, sufficient mold release rigidity can be obtained. If the amount of inorganic filler (C) is 50% by mass or less, it will not adversely affect the mechanical properties of the styrene-based resin composition. The inorganic filler (C) content is more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 10% by mass or more, and even more preferably 15% by mass or more in the resin composition. Furthermore, this content is more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0056] [Antioxidant (D)] The styrene-based resin composition of this embodiment preferably contains an antioxidant (D). Any known antioxidant can be used as the antioxidant (D) without any particular limitations, such as iodine compounds, phosphorus compounds, phenolic compounds, sulfur compounds, etc.

[0057] Specific examples of iodine compounds include potassium iodide, magnesium iodide, and ammonium iodide, but elemental iodine may also be used.

[0058] Examples of phosphorus compounds include monophosphites and diphosphites such as tris(2,4-di-tert-butylphenyl) phosphite and tris(mono and di-nonylphenyl) phosphite.

[0059] Specific examples of phenolic compounds include 2,6-di-tert-butyl-4-methylphenol, 2,6-diphenyl-4-methoxyphenol, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol], 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylenebis(4-methyl-6-nonylphenol), 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane, and ethylene glycol-bis[3,3-bis(3-tert- Examples include 1,1-(3,5-dimethyl-2-hydroxyphenyl)-3-(n-dodecylthio)-butane, 4,4'-thiobis(6-tert-butyl-3-methylphenol), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate dioctadecyl ester, n-octadecyl-3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate, pentaerythritol tetrakis{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate}, and N,N'-(hexane-1,6-diyl)bis(3,5-di-tert-butyl-4-hydroxybenzenepropanamide).

[0060] Specific examples of sulfur compounds include bis[3-(dodecylthio)propionic acid]2,2-bis[[3-(dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl.

[0061] The styrene-based resin composition may contain one or more of the aforementioned antioxidants simultaneously. From the viewpoint of suppressing deterioration of the molded article and providing heat resistance, the content of antioxidant (D) in the styrene-based resin composition is preferably 0.05 to 3.0% by mass, more preferably 0.1 to 1.0% by mass, and even more preferably 0.15 to 0.6% by mass. Furthermore, if the antioxidant content is 0.05% by mass or more, the molding operation can be performed smoothly, and if the amount of antioxidant is 3.0% by mass or less, the bleeding of the antioxidant can be suppressed, and the appearance will not be adversely affected.

[0062] [Other ingredients] The styrene-based resin composition of this embodiment may contain other components that are commonly used, such as crosslinking agents, crosslinking aids, fatty acid metal salts, nucleating agents, plasticizers, mold release agents, colorants, and / or antistatic agents, as long as they do not hinder the objectives of the present invention.

[0063] As fatty acid metal salts, metal salts of higher fatty acids having 16 to 22 carbon atoms are preferred, and specifically, examples include metal stearate salts such as aluminum stearate, calcium stearate, magnesium stearate, and zinc stearate.

[0064] As a nucleating agent, any known metal salts of carboxylic acids, including aluminum di(p-tert-butylbenzoate), metal salts of phosphoric acid, including methylenebis(2,4-di-tert-butylphenol) acid phosphate sodium, and phthalocyanine derivatives can be arbitrarily selected and used.

[0065] As a mold release agent, any known substances such as polyethylene wax, silicone oil, and long-chain carboxylic acids can be arbitrarily selected and used.

[0066] The styrene-based resin composition of this embodiment can be obtained by compounding and kneading a resin (A) and a compatibilizer (B) with components (C) to (D) and other components as needed. Compounding and kneading can be carried out by pre-mixing with commonly used equipment, such as a ribbon blender, drum tumbler, or Henschel mixer, followed by the use of a Banbury mixer, single-screw extruder, twin-screw extruder, multi-screw extruder, or conical mixer.

[0067] <Molded body> The molded article of this embodiment can be obtained by molding the styrene-based resin composition. That is, the molded article of this embodiment can be manufactured as various molded articles by injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, and foam molding, using the melt-kneaded styrene-based resin composition or pellets obtained in advance by melt-kneading as raw materials. The molded article thus obtained contains the styrene-based resin composition of this embodiment. In particular, pellets obtained by melt-kneading can be suitably used in the manufacture of injection-molded articles by injection molding and injection compression molding.

[0068] The molded article of this embodiment has good mechanical properties. Specifically, these mechanical properties include tensile properties, Charpy impact strength, and bending properties.

[0069] The tensile properties can be evaluated by the tensile modulus, tensile breaking strength, and tensile elongation obtained from a tensile test of a 4 mm thick dumbbell-shaped test piece obtained by molding the styrene-based resin composition of this embodiment, as described in the examples. The styrene-based resin composition of this embodiment can exhibit these properties well. Here, the tensile modulus of the styrene-based resin composition of this embodiment is preferably 10,000 MPa or higher, more preferably 10,500 MPa or higher, and even more preferably 11,000 MPa or higher, from the viewpoint of further improving the mechanical strength of the resulting molded article. From the viewpoint of further improving the mechanical strength of the resulting molded article, the higher the tensile modulus, the better. As the tensile breaking strength, from the viewpoint of further improving the mechanical strength of the obtained molded article, it is preferably 170 MPa or more, more preferably 180 MPa or more, still more preferably 190 MPa or more. From the viewpoint of further improving the mechanical strength of the obtained molded article, the higher the tensile breaking strength, the more preferable. As the tensile elongation at break, from the viewpoint of further improving the mechanical strength of the obtained molded article, it is preferably 2.0% or more, more preferably 2.5% or more, still more preferably 3.0% or more. From the viewpoint of further improving the mechanical strength of the obtained molded article, the higher the tensile elongation at break, the more preferable. These tensile properties can be obtained by known measuring methods, and specifically, the method described in the examples can be mentioned.

[0070] In addition, the mechanical properties can be evaluated by the Charpy impact strength of a 4 mm thick plate obtained by molding the styrene resin composition of the present embodiment as described in the examples. This Charpy impact strength, from the viewpoint of improving the impact resistance of the obtained molded article, for example, the Charpy impact strength without notch is preferably 45 kJ / m 2 or more, more preferably 50 kJ / m 2 or more, still more preferably 55 kJ / m 2 or more. From the viewpoint of further improving the impact resistance of the obtained molded article, the higher the Charpy impact strength, the more preferable.

[0071] In addition, as the bending properties, they can be evaluated by the bending strength, bending modulus of elasticity, etc. obtained by a bending test of a 4 mm thick plate obtained by molding the styrene resin composition of the present embodiment as described in the examples. The styrene resin composition of the present embodiment can have good these properties. Here, as the bending strength in the styrene resin composition of the present embodiment, from the viewpoint of further improving the mechanical strength of the obtained molded article, it is preferably 210 MPa or more, more preferably 230 MPa or more, still more preferably 250 MPa or more. From the viewpoint of further improving the mechanical strength of the obtained molded article, the higher the bending strength, the more preferable. From the viewpoint of further improving the mechanical strength of the resulting molded article, the flexural modulus is preferably 10,000 MPa or higher, more preferably 10,200 MPa or higher, and even more preferably 10,300 MPa or higher. From the viewpoint of further improving the mechanical strength of the resulting molded article, the higher the flexural modulus, the better.

[0072] Furthermore, the molded article of this embodiment can also be a molded article with low water absorption. Low water absorption can be evaluated by measuring the water absorption rate, and if this value is small, the amount of water contained in the molding material pellets, etc., is small during the manufacture of the molded article (especially high-voltage components), and the production efficiency of the molded product can be improved without the formation of blisters. The water absorption rate of the molded article is preferably 0.70% or less, more preferably 0.40% or less, and even more preferably 0.30% or less. The water absorption rate can be obtained by known measurement methods, specifically the method described in the examples.

[0073] The molded articles of this embodiment have excellent mechanical properties and are therefore suitable for electrical and electronic equipment materials, automotive parts (especially parts for hybrid and electric vehicles), and more specifically, they can be preferably used in applications such as automotive sensors, housings, connectors, terminal blocks, fuse components, batteries, motors, and other high-voltage components, and are particularly suitable for use as components around automotive batteries and motors. [Examples]

[0074] The present invention will be described in more detail by reference to examples, but the present invention is not limited thereto.

[0075] Pellet creation Each component except inorganic filler (C) was blended in the proportions listed in Table 1 and dry-blended in a Henschel mixer. Subsequently, the resin composition was kneaded using a twin-screw kneader with a cylinder diameter of 37 mm (Toshiba Machine Co., Ltd.: TEM37SS) at a screw rotation speed of 250 rpm and a barrel temperature of 290°C or 330°C, while side-feeding inorganic filler (C) in the proportions listed in Tables 1 and 2, to produce pellets. The obtained pellets were dried in a vacuum dryer at 80°C or 120°C for 5 hours.

[0076] As described above, the pellets (resin composition) obtained after drying were evaluated. The physical properties of each example and comparative example were evaluated as follows. (1) Melt Flow Rate (MFR) The aforementioned The values ​​were measured using pellets obtained from the process, in accordance with ISO 1133, under conditions of 300°C or 330°C and 2.16 kg.

[0077] (2) Tensile test The aforementioned Using the pellets obtained, dumbbell-shaped tensile test specimens (Type A) were molded using an injection molding machine [Sumitomo Heavy Industries SE100EVA] under molding conditions of cylinder temperature 300°C or 330°C and mold temperature 80°C or 130°C, in accordance with JIS K7139:2015. These specimens were mounted on a tensile testing machine, and the tensile modulus, tensile breaking strength, and tensile breaking elongation were measured at a measurement temperature of 23°C, in accordance with ISO 527-1:2019.

[0078] (3) Charpy impact strength The aforementioned Using the pellets obtained, a strip-shaped test piece for evaluating mechanical properties, measuring 80 mm in length, 10 mm in width, and 4 mm in thickness, was injection molded using an injection molding machine [Sumitomo Heavy Industries SE100EVA] under the molding conditions of a cylinder temperature of 300°C or 330°C and a mold temperature of 80°C or 130°C. Furthermore, using the unprocessed, notched test piece, the Charpy impact value (kJ / m²) at 23°C was measured in accordance with ISO 179-1:2010 using a Charpy impact tester (Model 611, Toyo Seiki Seisakusho Co., Ltd.). 2 ) was measured.

[0079] (4) HDT (Thermal Distortion Temperature) The aforementioned Using the pellets obtained, HDT test specimens (80 mm in length, 10 mm in width, and 4 mm in thickness) were fabricated by injection molding using an injection molding machine [SE100EVA manufactured by Sumitomo Heavy Industries, Ltd.] at a cylinder temperature of 300°C or 330°C and a mold temperature of 80°C or 130°C. Using this HDT test specimen, the HDT (heat distortion temperature) was measured at a load of 1.8 MPa in accordance with ISO 75-1,2.

[0080] (5) Bending test The aforementioned Using the pellets obtained, 4 mm thick bending test specimens were prepared by injection molding using an injection molding machine [Sumitomo Heavy Industries SE100EVA] at a cylinder temperature of 300°C or 330°C and a mold temperature of 80°C or 130°C. Bending strength and bending modulus were measured in accordance with ISO 178:2010 under conditions of a support distance of 4 cm, a temperature of 23°C, and a bending speed of 2 mm / min.

[0081] (6) Water absorption rate The aforementioned Using the pellets obtained, a molded body was produced using an injection molding machine [SE100EVA manufactured by Sumitomo Heavy Industries, Ltd.] under the molding conditions of a cylinder temperature of 300°C or 330°C and a mold temperature of 80°C or 130°C. A chuck portion was obtained as a test specimen from the molded body by cutting. The water absorption rate was measured using this test specimen in accordance with ISO 62 Method A.

[0082] Examples 1-3 and Comparative Examples 1-16 Each component was blended in the proportions shown in Tables 1 and 2, and various evaluations were performed according to the molding conditions described above. The components used are as follows:

[0083] <Resin (A)> [Component (A1)] SPS: Styrene resin with syndiotactic structure [Manufactured by Idemitsu Kosan Co., Ltd.; weight-average molecular weight 200,000, MFR 9.0g / 10 min (temperature 300℃, load 1.2kg)] [(A2) Component: Polyamide having a 6T structure] Polyamide 6T (PA6T): NHU-PPA N200 [Manufactured by Zhejiang NHU Special Materials Co., Ltd., trade name; copolymer having polyamide 6T structure / 6I structure / 66 structure, melting point: 313℃]

[0084] [(A2') component: Polyamide without a 6T structure] Polyamide 66 (PA66): Vydyne® 50BWFS [Manufactured by Ascend Performance Materials, trade name: Nylon 66, melting point 265°C] Polyamide 9T (PA9T): A polyamide obtained by the following manufacturing method [intrinsic viscosity [η]: 1.2 dl / g, terminal amino group content: 40 mmol / kg, melting point: 300°C, glass transition temperature: 125°C].

[0085] (Method for producing polyamide 9T) The raw materials were placed in a 20-liter autoclave and purged with nitrogen. The mixture consisted of 4537.7 g (27.3 mol) of terephthalic acid, 4385 g (27.5 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [1,9-nonanediamine / 2-methyl-1,8-octanediamine = 80 / 20 (molar ratio)], 41.5 g (0.34 mol) of benzoic acid, 9.12 g of sodium hypophosphate monohydrate (0.1% by mass relative to the total mass of the raw materials), and 2.5 liters of distilled water. The mixture was stirred at 100°C for 30 minutes, and the temperature inside the autoclave was raised to 220°C over 2 hours. During this time, the pressure inside the autoclave was increased to 2 MPa. The reaction continued for 2 hours, then the temperature was raised to 230°C, and the temperature was maintained at 230°C for another 2 hours, while the water vapor was gradually released and the pressure was kept at 2 MPa. Next, the pressure was reduced to 1 MPa over 30 minutes, and the reaction was continued for another hour to obtain a prepolymer with an intrinsic viscosity [η] of 0.15 dl / g. This was dried at 100°C under reduced pressure for 12 hours and pulverized to a particle size of 2 mm or less. This was then prepared by solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polyamide resin 9T.

[0086] <Compatibilizer (B)> Compatibilizer 1: Fumaric acid-modified polyphenylene ether [manufactured by Idemitsu Kosan Co., Ltd.; modification rate 1.5% by mass] <Inorganic filler (C)> Glass fiber 1: ECS03T-249H [Manufactured by Nippon Electric Glass Co., Ltd., product name: E-glass, fibrous (chopped strand length 3 mm), fiber cross-section approximately circular (φ10.5 μm), treated with silane coupling agent] Glass fiber 2: CSX-3J-451S [Manufactured by Nitto Boseki Co., Ltd., product name; fibrous (chopped strand length 3 mm), fiber cross-section approximately circular (φ11 μm), treated with silane coupling agent] <Antioxidant (D)> Antioxidant 1: Irganox 1098 [Manufactured by BASF Japan Ltd., product name: Hindered phenol antioxidant] <Other> Nuclear agent 1: ADEKA stab NA-11 [Manufactured by ADEKA Corporation, product name]

[0087] [Table 1]

[0088] [Table 2]

[0089] From the results of Examples 1-3 and Comparative Examples 1-7, it was found that the styrene-based resin composition of the present invention, by containing SPS resin (A1) and a polyamide (A2) having a specific structure in predetermined proportions in resin (A), can be used to obtain molded articles with excellent mechanical properties. Furthermore, these molded articles exhibited low water absorption and good water resistance.

[0090] Furthermore, the results from Examples 1-3 and Comparative Examples 8-16 confirmed that the excellent mechanical properties achieved by including the above-mentioned SPS resin (A1) and a polyamide having a specific structure (A2) in predetermined proportions are a result of using a polyamide having a polyamide 6T structure.

Claims

1. A styrene resin composition comprising a resin (A) containing a styrene resin (A1) and a polyamide (A2) having a syndiotactic structure, and a compatibilizer (B) having polar groups that are compatible with the styrene resin (A1) and reactable with the polyamide (A2), The polyamide (A2) comprises a component unit (A2a) derived from a dicarboxylic acid and a component unit (A2b) derived from a diamine. The polyamide (A2) has a polyamide 6T structure in which a component unit (A2a) derived from terephthalic acid and a component unit (A2b) derived from 1,6-diaminohexane are adjacent to each other. A styrene-based resin composition in which the mass ratio [(A2) / (A1)] of the polyamide (A2) to the styrene-based resin (A1) is 55 / 45 to 95 / 5.

2. The styrene-based resin composition according to claim 1, further comprising, as the component unit (A2a) derived from the dicarboxylic acid, at least one selected from the group consisting of component units derived from isophthalic acid and component units derived from adipic acid.

3. The styrene-based resin composition according to claim 1 or 2, wherein the polyamide (A2) mainly comprises the polyamide 6T structure.

4. The styrene-based resin composition according to any one of claims 1 to 3, wherein the melting point of the polyamide (A2) is 300°C or higher and 340°C or lower.

5. The styrene-based resin composition according to any one of claims 1 to 4, wherein the total content of the polyamide (A2) and the styrene-based resin (A1) is 30% by mass or more and 99% by mass or less in the styrene-based resin composition.

6. The styrene-based resin composition according to any one of claims 1 to 5, wherein the compatibilizer (B) is one or more selected from the group consisting of modified polyphenylene ether and modified polystyrene.

7. The styrene-based resin composition according to any one of claims 1 to 6, wherein the content of the compatibilizer (B) is 1% by mass or more and 5% by mass or less in the styrene-based resin composition.

8. Furthermore, the styrene-based resin composition according to any one of claims 1 to 7, further comprising an inorganic filler (C).

9. The styrene-based resin composition according to claim 8, wherein the inorganic filler (C) is a glass filler.

10. The styrene-based resin composition according to claim 8 or 9, wherein the content of the inorganic filler (C) is 10% by mass or more and 40% by mass or less in the styrene-based resin composition.

11. Furthermore, the styrene resin composition according to any one of claims 1 to 10, further containing an antioxidant (D).

12. The styrene-based resin composition according to claim 11, wherein the content of the antioxidant (D) is 0.05% by mass or more and 3.0% by mass or less in the styrene-based resin composition.

13. The styrene-based resin composition according to any one of claims 1 to 12, wherein the melt flow rate (MFR) of the styrene-based resin composition at 330°C is 2 g / 10 min or more and 30 g / 10 min or less.

14. A molded article containing the styrene-based resin composition according to any one of claims 1 to 13.

15. The molded article according to claim 14, wherein the tensile breaking strength is 170 MPa or more.

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