Polyarylene sulfide composition

Abstract

To provide a polyarylene sulfide composition excellent in electric characteristics such as tracking resistance, mechanical strength, toughness, flame retardancy, dimensional stability and melt flowability, and useful for electric parts such as electric and electronic parts and automobile electric parts, especially for electric parts used under high voltage such as a case of an insulated gate bipolar transistor module which is a large capacity power module.SOLUTION: A polyarylene sulfide composition comprising, based on 100 parts by weight of a polyarylene sulfide (A), at least 3 to 45 parts by weight of an ethylene-vinyl alcohol-based polymer (B) having a melt flow rate of 3 to 1050g / 10 minutes, 0.5 to 30 parts by weight of a polyolefin-based elastomer (C), 50 to 200 parts by weight of magnesium hydroxide (D), and 50 to 200 parts by weight of a fibrous filler (E) having a flat cross-sectional shape.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyarylene sulfide composition that exhibits excellent electrical properties such as tracking resistance, as well as excellent mechanical strength, toughness, melt fluidity, and dimensional stability, without impairing the heat resistance, chemical resistance, flame retardancy, and other properties inherent to polyarylene sulfide. More specifically, the present invention relates to a polyarylene sulfide composition that is useful for electrical component applications such as electric / electronic components and automotive electrical components, particularly for electrical component applications used under high voltage, such as cases for insulated gate bipolar transistor modules, which are large-capacity power modules. [Background technology]

[0002] Polyarylene sulfide is a resin that exhibits excellent properties such as heat resistance, chemical resistance, and flame retardancy, and taking advantage of these excellent properties, it is widely used in electrical and electronic equipment components, automotive equipment components, office equipment components, etc.

[0003] However, polyarylene sulfide has significantly inferior tracking resistance compared to other engineering plastics such as polybutylene terephthalate, and therefore its use in applications where it is exposed to relatively high voltages has been limited.

[0004] Several attempts have been made to improve the tracking resistance of polyarylene sulfide, and proposals have been made, for example, of a resin composition containing (a) polyphenylene sulfide, (b) polyamide, and (c) a metal hydroxide whose main component is magnesium hydroxide (see, for example, Patent Document 1); a resin composition containing (a) polyarylene sulfide, (b) one or more polymers selected from polyolefin (co)polymers, silicones, and fluorine-based resins, (c) magnesium hydroxide, and (d) a fibrous and / or non-fibrous filler (see, for example, Patent Document 2); and a resin composition containing (a) polyphenylene sulfide, (b) magnesium hydroxide having a specific average particle size and a specific particle size distribution, and (c) a fibrous and / or non-fibrous filler (see, for example, Patent Document 3).

[0005] Furthermore, as a resin composition having improved tracking resistance and mechanical strength of polyarylene sulfide, a polyphenylene sulfide resin composition consisting of (a) polyphenylene sulfide, (b) an ethylene-vinyl alcohol copolymer, (c) magnesium hydroxide, and (d) a flat-shaped fibrous filler (see, for example, Patent Document 4), and as a resin composition having improved tracking resistance and toughness, a polyphenylene sulfide resin composition consisting of (a) polyphenylene sulfide, (b) an ethylene-vinyl alcohol copolymer, (c) magnesium hydroxide, (d) a hydrogenated product of a modified vinyl aromatic compound block copolymer modified with a carboxylic acid group or a derivative group thereof, and (e) a fibrous filler (see, for example, Patent Document 5), have been proposed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 05-271542 [Patent Document 2] Japanese Patent Application Publication No. 08-291253 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-288363 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-145006 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-28112 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the resin compositions proposed in Patent Documents 1 to 3 have problems in that their tracking resistance is still not fully satisfactory and they generate a large amount of gas during molding. Furthermore, in order to obtain sufficiently excellent tracking resistance, these proposed resin compositions require a high magnesium hydroxide content, which not only results in poor mechanical strength and toughness, but also in significantly poor melt fluidity. The resin composition proposed in Patent Document 4 has good mechanical strength but poor toughness, and the resin composition proposed in Patent Document 5 has good toughness but poor flame retardancy.

[0008] That is, it has generally been difficult for these resin compositions to simultaneously achieve excellent tracking resistance, high mechanical strength, high toughness, good melt flowability, dimensional stability, and flame retardancy.

[0009] Therefore, an object of the present invention is to provide a polyarylene sulfide composition that has excellent tracking resistance, as well as excellent mechanical strength and toughness, and also excellent melt flowability, dimensional stability, and flame retardancy. More specifically, an object of the present invention is to provide a polyarylene sulfide composition that is useful for electrical part applications such as electric / electronic parts or automotive electrical parts, particularly for electrical part applications such as cases for electrical parts, and particularly for electrical part applications used under high voltages, such as cases for insulated gate bipolar transistor modules, which are large-capacity power modules. [Means for solving the problem]

[0010] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that a polyarylene sulfide composition comprising polyarylene sulfide, a specific ethylene-vinyl alcohol copolymer, a polyolefin elastomer, magnesium hydroxide, and a fibrous filler having a flat cross-sectional shape can be a composition that has excellent tracking resistance, as well as excellent mechanical strength, toughness, and flame retardancy, generates a small amount of gas during molding, and is also excellent in melt fluidity, mold releasability, mold contamination resistance, and appearance of molded products, and have thereby completed the present invention.

[0011] That is, the present invention relates to a polyarylene sulfide composition comprising, per 100 parts by weight of polyarylene sulfide (A), at least 3 to 45 parts by weight of an ethylene-vinyl alcohol copolymer (B), which is an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer and / or an ethylene-vinyl alcohol copolymer, having a melt flow rate of 3 to 1050 g / 10 min, as measured with a Koka-type flow tester using a die having a diameter of 1 mm and a length of 2 mm under conditions of a measurement temperature of 190°C and a load of 2.16 kg, and 0.5 to 30 parts by weight of a polyolefin elastomer (C), 50 to 200 parts by weight of magnesium hydroxide (D), and 50 to 200 parts by weight of a fibrous filler (E) having a flat cross section.

[0012] The present invention will be described in detail below.

[0013] The polyarylene sulfide composition of the present invention contains, per 100 parts by weight of polyarylene sulfide (A), at least 3 to 45 parts by weight of an ethylene-vinyl alcohol copolymer (B) which is an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer and / or an ethylene-vinyl alcohol copolymer, having a melt flow rate of 3 to 1050 g / 10 min, as measured with a Koka type flow tester using a die having a diameter of 1 mm and a length of 2 mm under conditions of a measurement temperature of 190°C and a load of 2.16 kg, 0.5 to 30 parts by weight of a polyolefin elastomer (C), 50 to 200 parts by weight of magnesium hydroxide (D), and 50 to 200 parts by weight of a fibrous filler (E) having a flat cross section.

[0014] As the polyarylene sulfide (A) constituting the polyarylene sulfide composition of the present invention, any substance may be used as long as it belongs to the category called polyarylene sulfide. Among them, polyarylene sulfides having a melt viscosity of 50 to 2000 poises, as measured with a high-temperature flow tester using a die having a diameter of 1 mm and a length of 2 mm under conditions of a measurement temperature of 315°C and a load of 10 kg, are preferred, and those having a melt viscosity of 100 to 800 poises are particularly preferred, because the resulting polyarylene sulfide composition will have excellent mechanical strength and moldability.

[0015] The polyarylene sulfide (A) preferably contains p-phenylene sulfide units in an amount of 70 mol % or more, particularly 90 mol % or more, as its constituent units. It may also contain other constituent units such as m-phenylene sulfide units, o-phenylene sulfide units, phenylene sulfone units, phenylene sulfide ketone units, phenylene sulfide ether units, diphenylene sulfide units, substituted phenylene sulfide units, and branched phenylene sulfide units, and among these, poly(p-phenylene sulfide) is preferred.

[0016] The method for producing the polyarylene sulfide (A) is not particularly limited, and it can be produced, for example, by a method of reacting an alkali metal sulfide with a dihaloaromatic compound in a commonly known polymerization solvent. Examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof, and these may be used in the form of a hydrate. These alkali metal sulfides are obtained by reacting an alkali metal hydrosulfide with an alkali metal base, and may be prepared in situ prior to adding the dihaloaromatic compound to the polymerization system, or may be prepared outside the system. Examples of the dihaloaromatic compound include p-dichlorobenzene, p-dibromobenzene, p-diiodobenzene, m-dichlorobenzene, m-dibromobenzene, m-diiodobenzene, 1-chloro-4-bromobenzene, 4,4'-dichlorodiphenylsulfone, 4,4'-dichlorodiphenyl ether, 4,4'-dichlorobenzophenone, 4,4'-dichlorodiphenyl, etc. The charging ratio of the alkali metal sulfide and the dihaloaromatic compound is preferably in the range of alkali metal sulfide / dihaloaromatic compound (molar ratio) = 1.00 / 0.90 to 1.10.

[0017] As the polymerization solvent, polar solvents are preferred, and organic amides, which are aprotic and stable to alkalis at high temperatures, are particularly preferred. Examples of such organic amides include N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoramide, N-methyl-ε-caprolactam, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, dimethyl sulfoxide, sulfolane, tetramethylurea, and mixtures thereof. The polymerization solvent is preferably used in an amount of 150 to 3500 wt %, and more preferably 250 to 1500 wt %, based on the polymer produced by polymerization. The polymerization is preferably carried out at 200 to 300°C, particularly 220 to 280°C, for 0.5 to 30 hours, particularly 1 to 15 hours, with stirring.

[0018] Furthermore, the polyarylene sulfide (A) may be a straight-chain one, one crosslinked by treatment at high temperature in the presence of oxygen, one to which a small amount of a trihalo or higher polyhalo compound has been added to introduce a slight crosslinking or branched structure, one to which a heat treatment has been performed in a non-oxidizing inert gas such as nitrogen, or a mixture of these structures.

[0019] The ethylene-vinyl alcohol copolymer (B) constituting the present invention is an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer and / or an ethylene-vinyl alcohol copolymer having a melt flow rate of 3 to 1050 g / 10 min, as measured with a Koka type flow tester using a die of 1 mm diameter and 2 mm length at a measurement temperature of 190°C and a load of 2.16 kg, and preferably 3 to 500 g / 10 min, since this results in particularly excellent tracking resistance, toughness, and melt fluidity. The ethylene-vinyl alcohol copolymer (B) is used to improve the tracking resistance and toughness of the polyarylene sulfide composition.

[0020] The ethylene-vinyl alcohol copolymer may be any copolymer that falls within the category of an ethylene-vinyl alcohol copolymer or an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer. Examples of the ethylene-fatty acid vinyl ester-vinyl alcohol copolymer include an ethylene-vinyl acetate-vinyl alcohol copolymer, an ethylene-vinyl propionate-vinyl alcohol copolymer, an ethylene-vinyl butyrate-vinyl alcohol copolymer, an ethylene-vinyl caproate-vinyl alcohol copolymer, an ethylene-vinyl octanoate-vinyl alcohol copolymer, and an ethylene-vinyl 2-hexyl hexanoate-vinyl alcohol copolymer. Ethylene-vinyl alcohol copolymers and ethylene-vinyl acetate-vinyl alcohol copolymers are particularly preferred because they provide an excellent balance of tracking resistance, toughness, and melt fluidity. When the melt flow rate of the ethylene-vinyl alcohol copolymer is less than 3 g / 10 min, the melt fluidity is poor. On the other hand, when the melt flow rate of the ethylene-vinyl alcohol copolymer is greater than 1050 g / 10 min, the tracking resistance and toughness are poor.

[0021] The ethylene-vinyl alcohol copolymer (B) is preferably an ethylene-vinyl alcohol copolymer and / or an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer represented by the following general formula (1), since these copolymers simultaneously have particularly high tracking resistance, good mechanical strength and toughness, and produce a polyarylene sulfide composition that generates a small amount of gas during molding.

[0022] [ka]

[0023] (wherein x = 0.25 to 0.90, y = 0 to 0.08, z = 0.02 to 0.75, x + y + z = 1, and R is a hydrocarbon group having 1 to 10 carbon atoms.) R is a hydrocarbon group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, etc. In particular, an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer and / or an ethylene-vinyl alcohol copolymer, in which x=0.50 to 0.90, y=0 to 0.08, and z=0.10 to 0.50, is preferred.

[0024] The method for producing the ethylene-vinyl alcohol copolymer (B) is not particularly limited, and it can be obtained by, for example, a method of copolymerizing an ethylene monomer, a fatty acid vinyl ester monomer, and a vinyl alcohol monomer, a method of (partially) saponifying an ethylene-fatty acid vinyl ester copolymer, etc. Among these, an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer and an ethylene-vinyl alcohol copolymer obtained by (partially) saponifying an ethylene-fatty acid vinyl ester copolymer are preferred because they are easily available industrially.

[0025] The amount of the ethylene-vinyl alcohol copolymer (B) contained in the polyarylene sulfide composition of the present invention is 3 to 45 parts by weight based on 100 parts by weight of the polyarylene sulfide (A). If the amount of the ethylene-vinyl alcohol copolymer (B) is less than 3 parts by weight, the resulting composition will be inferior in tracking resistance and toughness. On the other hand, if the amount of the ethylene-vinyl alcohol copolymer (B) is more than 45 parts by weight, the resulting composition will be inferior in heat resistance and flame retardancy.

[0026] The polyolefin elastomer (C) constituting the polyarylene sulfide composition of the present invention is used to improve the toughness of the polyarylene sulfide composition, and may be any elastomer that falls within that category, such as a polyethylene elastomer or a polypropylene elastomer. Among these, a polyethylene elastomer is preferred because, in particular, when combined with the ethylene-vinyl alcohol copolymer (B), it simultaneously improves the toughness and tracking resistance of the polyarylene sulfide composition without impairing its heat resistance. In particular, at least one modified ethylene copolymer selected from the group consisting of an ethylene-α,β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymer, an ethylene-α,β-unsaturated carboxylic acid glycidyl ester copolymer, an ethylene-α,β-unsaturated carboxylic acid glycidyl ester-vinyl acetate copolymer, an ethylene-α,β-unsaturated carboxylic acid glycidyl ester-α,β-unsaturated carboxylic acid alkyl ester copolymer, and a maleic anhydride-grafted modified ethylene-α-olefin copolymer is preferred. If a material other than a polyolefin elastomer is used, the tracking resistance, heat resistance, etc. will be poor.

[0027] Any ethylene-α,β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymer may be used as long as it falls within this category, and in particular, since the resulting polyarylene sulfide composition has excellent toughness such as elongation, it is preferable that the weight ratio of ethylene units:α,β-unsaturated carboxylic acid alkyl ester units:maleic anhydride units is in the range of 50 to 98:40 to 1:10 to 1. Specific examples of the ethylene-α,β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymer include (trade name) Bondine LX4110 (manufactured by SK Global Chemical Co., Ltd.), (trade name) Bondine TX8030 (manufactured by SK Global Chemical Co., Ltd.), (trade name) Bondine AX8390 (manufactured by SK Global Chemical Co., Ltd.), etc.

[0028] Any ethylene-α,β-unsaturated carboxylic acid glycidyl ester copolymer may be used as long as it falls within this category, and in particular, since the resulting polyarylene sulfide composition has excellent toughness such as elongation, it is preferable that the weight ratio of ethylene units to α,β-unsaturated carboxylic acid glycidyl ester units is in the range of 85 to 99:15 to 1. Specific examples of the ethylene-α,β-unsaturated carboxylic acid glycidyl ester copolymer include (trade name) Bondine AX8840 (manufactured by SK Global Chemical Co., Ltd.) and (trade name) Bondfast E (manufactured by Sumitomo Chemical Co., Ltd.).

[0029] The ethylene-α,β-unsaturated carboxylic acid glycidyl ester-vinyl acetate copolymer may be any copolymer that falls within this category, and in particular, since the resulting polyarylene sulfide composition has excellent toughness such as elongation, it is preferable that the weight ratio of ethylene units:α,β-unsaturated carboxylic acid glycidyl ester units:vinyl acetate units is in the range of 50 to 98:15 to 1:35 to 1. Specific examples of the ethylene-α,β-unsaturated carboxylic acid glycidyl ester-vinyl acetate copolymer include (trade name) Bondfast 2B (manufactured by Sumitomo Chemical Co., Ltd.) and (trade name) Bondfast 7B (manufactured by Sumitomo Chemical Co., Ltd.).

[0030] The ethylene-α,β-unsaturated carboxylic acid glycidyl ester-α,β-unsaturated carboxylic acid alkyl ester copolymer may be any copolymer that falls within this category, and in particular, since the resulting polyarylene sulfide composition has excellent toughness such as elongation, it is preferable that the weight ratio of ethylene units:α,β-unsaturated carboxylic acid glycidyl ester units:α,β-unsaturated carboxylic acid alkyl ester units is in the range of 50 to 98:10 to 1:40 to 1. Specific examples of the ethylene-α,β-unsaturated carboxylic acid glycidyl ester-α,β-unsaturated carboxylic acid alkyl ester copolymer include (trade name) Bondfast 7L (manufactured by Sumitomo Chemical Co., Ltd.), (trade name) Bondfast 7M (manufactured by Sumitomo Chemical Co., Ltd.), (trade name) LOTADER AX8700 (manufactured by SK Global Chemical Co., Ltd.), and (trade name) LOTADER AX8750 (manufactured by SK Global Chemical Co., Ltd.).

[0031] The maleic anhydride-grafted ethylene-α-olefin copolymer may be any copolymer that falls within this category, and among these, those having a weight ratio of ethylene units:α-olefin units:maleic anhydride units of 50 to 98:45 to 1:5 to 1 are preferred because the resulting polyarylene sulfide composition has excellent toughness such as elongation, and specific examples include maleic anhydride-grafted linear low-density polyethylene, maleic anhydride-grafted ethylene-propylene rubber, etc. The maleic anhydride-grafted ethylene-α-olefin copolymer can be obtained, for example, by carrying out a grafting reaction in the coexistence of an ethylene-α-olefin copolymer, a peroxide, and maleic anhydride.

[0032] The α-olefin constituting the ethylene copolymer refers to an α-olefin having 3 or more carbon atoms, such as propylene, butene-1, 4-methyl-pentene-1, hexene-1, and octene-1. Examples of the α,β-unsaturated carboxylic acid alkyl ester include alkyl esters of acrylic acid and methacrylic acid, specifically methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and t-butyl methacrylate. Examples of the α,β-unsaturated carboxylic acid glycidyl ester include acrylic acid glycidyl ester and methacrylic acid glycidyl ester.

[0033] The blending amount of the polyolefin elastomer (C) is 0.5 to 30 parts by weight per 100 parts by weight of the polyarylene sulfide (A), and is preferably 3 to 15 parts by weight, since this results in a polyarylene sulfide composition excellent in toughness, tracking resistance, and flame retardancy. If the blending amount of the polyolefin elastomer (C) is less than 0.5 parts by weight, the resulting resin composition will have poor cold toughness. On the other hand, if the blending amount exceeds 30 parts by weight, the resulting resin composition will have poor heat resistance and flame retardancy, which is undesirable.

[0034] As the magnesium hydroxide (D) constituting the polyarylene sulfide composition of the present invention, any substance belonging to the category called magnesium hydroxide may be used. Among them, magnesium hydroxide of relatively high purity containing 80% by weight or more of hydroxide represented by the chemical formula Mg(OH)2 is preferred because the resulting polyarylene sulfide composition will have excellent tracking resistance, melt fluidity, and high mechanical strength. Magnesium hydroxide having 80% by weight or more of hydroxide represented by the chemical formula Mg(OH)2, a CaO content of 5% by weight or less, and a chlorine content of 1% by weight or less is more preferred. Magnesium hydroxide having 95% by weight or more of Mg(OH)2, a CaO content of 1% by weight or less, and a chlorine content of 0.5% by weight or less is even more preferred. High-purity magnesium hydroxide having 98% by weight or more of Mg(OH)2, a CaO content of 0.1% by weight or less, and a chlorine content of 0.1% by weight or less is most preferred.

[0035] The magnesium hydroxide (D) forms a polyarylene sulfide composition that is particularly excellent in tracking resistance, toughness, mechanical strength, melt flowability, and molded product appearance. Therefore, the average particle diameter (D) measured by a laser diffraction scattering method is 50 ) is preferably in the range of 0.3 to 10 μm, and particularly preferably in the range of 0.5 to 3 μm. The specific surface area of ​​the magnesium hydroxide (D) is preferably 10 m or less, since this results in a polyarylene sulfide composition that is particularly excellent in tracking resistance, toughness, mechanical strength, and melt fluidity. 2 / g or less is preferable.

[0036] The magnesium hydroxide (D) may be surface-treated before use, if necessary. The surface coating agent is not particularly limited, and examples thereof include higher fatty acids and their metal salts, such as stearic acid, oleic acid, and alkali metal salts thereof; anionic surfactants, such as sulfates of higher alcohols; phosphates, such as esters of orthophosphoric acid and higher alcohols; silane coupling agents, such as vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane; titanate coupling agents, such as isopropyltriisostearoyltitanate; aluminum coupling agents, such as acetoalkoxyaluminum diisopropylate; and esters of polyhydric alcohols and fatty acids, such as glycerin monostearate. Among these magnesium hydroxides (D), surface-treated magnesium hydroxide is preferred, as it results in a polyarylene sulfide composition that is particularly excellent in toughness and mechanical strength.

[0037] The amount of magnesium hydroxide (D) contained in the polyarylene sulfide composition of the present invention is 50 to 200 parts by weight per 100 parts by weight of polyarylene sulfide (A), and is preferably 80 to 150 parts by weight, since this results in a polyarylene sulfide composition with an excellent balance of toughness, mechanical strength, and flame retardancy. If the amount of magnesium hydroxide (D) is less than 50 parts by weight, the resulting composition will have poor tracking resistance. On the other hand, if the amount of magnesium hydroxide (D) is more than 200 parts by weight, the resulting composition will have poor mechanical strength, toughness, and melt fluidity.

[0038] The fibrous filler (E) having a flat cross-sectional shape that constitutes the polyarylene sulfide composition of the present invention is blended to improve the mechanical strength, toughness, dimensional stability, and melt flowability of the polyarylene sulfide composition, and examples thereof include glass fibrous fillers, carbon fibrous fillers, and metal fibrous fillers, with glass fibrous fillers being particularly preferred. The fibrous filler having a flat cross-sectional shape is preferably one having a ratio of major axis to minor axis in the fiber cross section (major axis / minor axis) of 2 to 20, since this results in a polyarylene sulfide composition that is particularly well-balanced between mechanical strength and dimensional stability. Here, if the cross-sectional shape is not flat, i.e., if the cross-sectional shape is a fibrous filler having a circular, square, or other cross-sectional shape, the resulting polyarylene sulfide composition will be inferior in mechanical strength, toughness, and dimensional stability. Furthermore, the fibrous filler (E) having a flat cross-sectional shape is preferably surface-treated with an isocyanate compound, a silane coupling agent, a titanate coupling agent, an epoxy compound, or the like, since this will result in better mechanical strength of the polyarylene sulfide composition.

[0039] The amount of the fibrous filler (E) having a flat cross-sectional shape that constitutes the polyarylene sulfide composition of the present invention is 50 to 200 parts by weight per 100 parts by weight of polyarylene sulfide (A), and is preferably 80 to 150 parts by weight, since this results in a polyarylene sulfide composition that is particularly well-balanced between toughness, mechanical strength, and fluidity. If the amount of the fibrous filler (E) having a flat cross-sectional shape is less than 50 parts by weight, the resulting composition will have poor mechanical strength. On the other hand, if the amount of the fibrous filler (E) having a flat cross-sectional shape is more than 200 parts by weight, the resulting composition will have poor toughness and melt fluidity.

[0040] The polyarylene sulfide composition of the present invention exhibits particularly excellent moldability, and therefore may further contain a release agent. The release agent is preferably one or more selected from, for example, polyethylene wax, polypropylene wax, fatty acid amide lubricants, and carnauba wax. Commercially available polyethylene wax, polypropylene wax, fatty acid amide lubricants, and carnauba wax can be used. Examples of the fatty acid amide lubricant include polycondensates of higher fatty acid amides, ethylene bisstearamide, higher fatty acids, and diamines. Any lubricant within this category can be used, such as Light Amide WH-255 (manufactured by Kyoeisha Chemical Co., Ltd.), a polycondensate of stearic acid, sebacic acid, and ethylenediamine. The carnauba wax can be any wax commonly known as carnauba wax, such as Refined Carnauba Powder No. 1 (manufactured by Nikko Rica Corporation). The amount of the release agent to be added is preferably 0.1 to 3 parts by weight based on 100 parts by weight of the polyarylene sulfide (A).

[0041] The polyarylene sulfide composition of the present invention may be added with whiskers such as carbon fibers, silicon nitride whiskers, basic magnesium sulfate whiskers, barium titanate whiskers, potassium titanate whiskers, silicon carbide whiskers, boron whiskers, and zinc oxide whiskers; inorganic fibers such as rock wool, zirconia, barium titanate, silicon carbide, silica, and blast furnace slag; organic fibers such as wholly aromatic polyamide fibers, phenolic resin fibers, and wholly aromatic polyester fibers; or mineral fibers such as wollastonite and magnesium oxysulfate, within the range not impairing the effects of the present invention. Alternatively, the polyarylene sulfide composition of the present invention may be added with calcium carbonate, lithium carbonate, magnesium carbonate, zinc carbonate, mica, silica, talc, clay, calcium sulfate, kaolin, wollastonite, zeolite, silicon oxide, magnesium oxide, zirconium oxide, tin oxide, magnesium silicate, calcium silicate, calcium phosphate, magnesium phosphate, carbon black, hydrotalcite, glass powder, glass balloons, and glass flakes within the range not impairing the effects of the present invention.

[0042] Furthermore, the polyarylene sulfide composition of the present invention may contain one or more conventional additives such as a conventionally known crystal nucleating agent, plasticizer, antioxidant, heat stabilizer, or foaming agent, within the range that does not impair the effects of the present invention.

[0043] Furthermore, the polyarylene sulfide composition of the present invention may be prepared by mixing one or more of various thermosetting resins and thermoplastic resins, such as epoxy resins, cyanate ester resins, phenolic resins, polyimides, silicone resins, polyesters, polyamides, polyphenylene oxides, polycarbonates, polysulfones, polyetherimides, polyethersulfones, polyetherketones, polyetheretherketones, and polyamideimides, within the scope of the object of the present invention.

[0044] The method for producing the polyarylene sulfide composition of the present invention is not particularly limited, and any method known as a general mixing and kneading method can be used. For example, any method may be used, such as blending all raw materials and melt-kneading them; blending some of the raw materials and then melt-kneading them, and then blending and melt-kneading the remaining raw materials; or blending some of the raw materials and then melt-kneading them using a single-screw or twin-screw extruder, while mixing the remaining raw materials using a side feeder. Small amounts of additional components may be added by blending other components using the above-mentioned methods, pelletizing them, and then adding them before molding. The melt-kneading method may be a conventionally used heat-melt-kneading method, such as a heat-melt-kneading method using a single-screw or twin-screw extruder, kneader, mill, or Brabender. Melt-kneading using a twin-screw extruder, which has excellent kneading capabilities, is particularly preferred. The kneading temperature is not particularly limited, and can usually be selected from the range of 260 to 350°C.

[0045] The polyarylene sulfide composition of the present invention can be suitably used for various cases such as those for generators, electric motors, transformers, current transformers, voltage regulators, rectifiers, inverters, and capacitor plates. Among these, the polyarylene sulfide composition of the present invention has excellent tracking resistance, as well as excellent mechanical strength, toughness, and flame retardancy, and is excellent in dimensional stability and melt flowability. Therefore, the polyarylene sulfide composition can be particularly suitably used as a case for electrical components used under high voltage, for example, an insulated gate bipolar transistor (IGBT) module, which is a large-capacity power module.

[0046] The insulated gate bipolar transistor module case can be used as a case for large-capacity power modules and insulated gate bipolar transistor modules with a rated voltage of 1000 V or more and a rated current of 10 A or more, such as those used in inverters for railway vehicles, inverters for large uninterruptible power supplies, inverters for electric vehicle and hybrid vehicle motors, power conditioners for solar power generation and wind power generation, and inverters for large motors and elevators, and can improve their reliability. [Effects of the Invention]

[0047] The present invention provides a polyarylene sulfide composition that has excellent electrical properties such as tracking resistance, as well as excellent mechanical strength, toughness, and flame retardancy, and also has excellent dimensional stability and melt flowability. The polyarylene sulfide composition is useful for electrical component applications such as electric / electronic components and automotive electrical components, and as electrical component cases, particularly for electrical components used under high voltage, such as cases for insulated gate bipolar transistor modules, which are large-capacity power modules. [Example]

[0048] Next, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to these examples at all.

[0049] Details of the polyarylene sulfide (A), ethylene-vinyl alcohol copolymer (B), polyolefin elastomer (C), magnesium hydroxide (D), and fibrous filler (E) used in the examples and comparative examples are shown below.

[0050] <Polyarylene sulfide (A)> Poly(p-phenylene sulfide) (A-1) (hereinafter simply referred to as PPS (A-1)); melt viscosity 300 poise.

[0051] <Ethylene-vinyl alcohol copolymer (B) (hereinafter, may be referred to as VA copolymer (B))> Ethylene-vinyl alcohol copolymer (B-1) (hereinafter simply referred to as VA copolymer (B-1)); manufactured by Tosoh Corporation, x=0.802, y=0, z=0.198, melt flow rate 5.5 g / 10 min. Ethylene-vinyl alcohol copolymer (B-2) (hereinafter simply referred to as VA copolymer (B-2)); manufactured by Tosoh Corporation, x=0.820, y=0.020, z=0.160, melt flow rate 220 g / 10 min. Ethylene-vinyl acetate-vinyl alcohol copolymer (B-3) (hereinafter simply referred to as VA copolymer (B-3)); manufactured by Tosoh Corporation, x=0.820, y=0.020, z=0.160, melt flow rate 1000 g / 10 min. Ethylene-vinyl acetate-vinyl alcohol copolymer (B'-4) (hereinafter simply referred to as VA copolymer (B-4)); manufactured by Tosoh Corporation, x=0.820, y=0.020, z=0.160, melt flow rate 1160 g / 10 min.

[0052] <Polyolefin-based elastomer (C) (hereinafter, may be referred to as PO-based elastomer (C))> Elastomer (C-1): SK Global Chemical Co., Ltd., (trade name) Bondine AX8390, ethylene-α,β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymer. Elastomer (C-2): SK Global Chemical Co., Ltd., (trade name) Lotader AX8700, ethylene-α,β-unsaturated carboxylic acid glycidyl ester-α,β-unsaturated carboxylic acid alkyl ester copolymer. Elastomer (C'-3): Asahi Kasei Chemicals Corporation, trade name Tuftec M1943; hydrogenated acid-modified styrene-butadiene-styrene block copolymer containing 1.8% by weight of maleic anhydride and 19.6% by weight of styrene polymer block.

[0053] <Magnesium hydroxide (D) (hereinafter, sometimes referred to as Mg hydroxide (D))> Magnesium hydroxide (D-1): manufactured by Konoshima Chemical Co., Ltd., (trade name) Magseeds V6; Mg(OH) content 99.8% by weight, average particle size 1.0 μm, specific surface area 5.1 m 2 / g, surface treatment: vinyl silane.

[0054] <Fiber filler (E)> Glass fiber (E-1): manufactured by Nippon Electric Glass Co., Ltd., (product name) ECS-03T-747-FGF, ratio of major axis to minor axis in fiber cross section (major axis / minor axis) 4, fiber length 3 mm. Glass fiber (E-2): manufactured by Nitto Boseki Co., Ltd., (product name) CSG 3PL-830, ratio of major axis to minor axis in fiber cross section (major axis / minor axis) 4, fiber length 3 mm. Glass fiber (E-3): manufactured by Nitto Boseki Co., Ltd., ratio of major diameter to minor diameter in the fiber cross section (major diameter / minor diameter) 6, fiber length 3 mm. Glass fiber (E'-4): manufactured by Nippon Electric Glass Co., Ltd., (product name) ECS-03T-747, fiber diameter 10 μm, fiber length 3 mm, fiber cross section shape is circular.

[0055] Synthesis Example 1 (Synthesis of PPS (A-1)) A 15-liter autoclave equipped with a stirrer was charged with 1814 g of flake sodium sulfide (NaS·2.9H2O), 48 g of 30% caustic soda solution (30% NaOH aq), and 3679 g of N-methyl-2-pyrrolidone. The mixture was gradually heated to 200°C while stirring under a nitrogen stream, and 380 g of water was distilled off. After cooling to 190°C, 2107 g of p-dichlorobenzene and 985 g of N-methyl-2-pyrrolidone were added, and the system was sealed under a nitrogen stream. The system was heated to 225°C over 2 hours and polymerized at 225°C for 1 hour. The temperature was then raised to 250°C over 25 minutes, and polymerization continued at 250°C for another 3 hours. After polymerization, N-methyl-2-pyrrolidone was recovered from the polymerization slurry by distillation under reduced pressure. The resulting cake was washed with 80°C hot water to a slurry concentration of 20%, and then hot water was added again in the same manner, and the temperature was raised to 175°C, washing the poly(p-phenylene sulfide) twice in total. The resulting polyphenylene sulfide (a) was dried overnight at 105°C. The dried polyphenylene sulfide (a) was then loaded into a batch rotary kiln-type calciner, heated to 235°C in a nitrogen atmosphere, and held there for 2 hours for curing, yielding PPS (A-1) with a melt viscosity of 300 poise.

[0056] The evaluation and measurement methods used in the examples and comparative examples are shown below.

[0057] ~Measurement of tensile strength and tensile elongation~ Dumbbell test pieces for measuring tensile strength were prepared from the polyarylene sulfide composition using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., product name SE-75S) with a cylinder temperature of 310°C and a mold temperature of 140°C. Tensile strength was measured in accordance with ISO 527 using a tensile testing machine (manufactured by Shimadzu Corporation, product name Autograph AG-5000B). A tensile strength of 100 MPa or more was determined to have excellent mechanical strength. Furthermore, a tensile elongation of 1.0% or more was determined to have excellent toughness.

[0058] ~Charpy impact strength measurement~ The center of the dumbbell-shaped test piece for the tensile test was cut into a rod of 80 mm in length, 10 mm in width, and 4 mm in thickness, and notched to form an impact resistance test piece. A Charpy impact test was carried out in accordance with ISO179 to measure the Charpy impact strength (kJ / mm 2 ) was measured. The Charpy impact strength was 6.0 kJ / m 2 Those having the above properties were judged to have excellent mechanical strength.

[0059] ~Measurement of bar flow length~ The bar flow length (hereinafter referred to as BFL) was measured as an index of melt fluidity. A mold with a spiral groove 1 mm deep and 10 mm wide was attached to an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., (trade name) SE75). The polyarylene sulfide composition was then loaded into the hopper of the injection molding machine, with the cylinder temperature set to 310°C, the injection pressure set to 190 MPa, the injection speed set to the maximum, the injection time set to 1.5 seconds, and the mold temperature set to 135°C, and injected. The length of the melt flowing through the spiral groove in the mold was measured as BFL. A bar flow of 100 mm or more was considered to have excellent melt fluidity.

[0060] ~Dimensional stability~ The polyarylene sulfide composition was used to prepare flat plate test pieces measuring 70 mm in length, 70 mm in width, and 2 mm in thickness using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., product name: SE-75S) with a cylinder temperature of 310°C and a mold temperature of 140°C. The dimensions of the test pieces were measured in the longitudinal direction (MD) and transverse direction (TD). From the measured values, the mold shrinkage in each of the MD and TD directions was calculated using the formula "(mold dimension - measured value) / mold dimension x 100." Furthermore, the anisotropy of the mold shrinkage was calculated using the formula "TD mold shrinkage / MD mold shrinkage." A mold shrinkage anisotropy of 2.0 or less was determined to have excellent dimensional stability.

[0061] ~Flame retardant~ The polyarylene sulfide composition was used in an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., product name: SE-75S) with a cylinder temperature of 310°C and a mold temperature of 140°C to obtain a test piece for evaluating flame retardancy, 125 mm in length, 13 mm in width, and 1.6 mm in thickness. The flame retardancy of the test piece was evaluated in accordance with the evaluation criteria set forth in the UL94 vertical test. If the test piece did not meet the criteria equivalent to V-0, it was judged to be non-flame retardant. If the test piece was judged to be equivalent to V-0, it was judged to have excellent flame retardancy.

[0062] ~Measurement of tracking resistance~ The polyarylene sulfide composition was used to prepare disc-shaped test pieces with a diameter of 50 mm and a thickness of 3 mm using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., product name SE-75S) with a cylinder temperature of 310°C and a mold temperature of 140°C, and the comparative tracking index (hereinafter referred to as CTI) was measured using the test pieces in accordance with IEC 60112. A CTI of 600 (V) or more was determined to be excellent in tracking resistance.

[0063] Example 1 A mixture of 100 parts by weight of PPS (A-1), 10 parts by weight of VA copolymer (B-1), 10 parts by weight of elastomer (C-1), and 100 parts by weight of magnesium hydroxide (D-1) was charged into the hopper of a twin-screw extruder with a screw diameter of 25 mm (trade name: TEX-25αIII, manufactured by The Japan Steel Works, Ltd.) Separately, 100 parts by weight of glass fiber (E-1) was charged into the hopper of a side feeder of the twin-screw extruder and melt-kneaded at a cylinder temperature of 300°C to obtain a pelletized polyphenylene sulfide composition (hereinafter sometimes referred to as PPS composition). The resulting PPS composition was dried at 150°C for 5 hours.

[0064] The resulting PPS composition was then molded into test pieces using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., product name SE75S), and the test pieces were evaluated for tensile strength, Charpy impact strength, tracking resistance, etc. The results are shown in Table 1.

[0065] Examples 2 to 9 A PPS composition was obtained and evaluated in the same manner as in Example 1, except that the ethylene-vinyl alcohol copolymer (B), elastomer (C), magnesium hydroxide (D), and fibrous filler (E) and their amounts were changed as shown in Table 1. The results are shown in Table 1.

[0066] [Table 1]

[0067] Comparative Examples 1 to 10 Resin compositions were obtained and evaluated in the same manner as in Example 1, except that the ethylene-vinyl alcohol copolymer (B), elastomer (C), magnesium hydroxide (D), and fibrous filler (E) and their amounts were changed as shown in Table 2. The results are shown in Table 2.

[0068] [Table 2]

[0069] The resin composition obtained in Comparative Example 1 was poor in mechanical strength and toughness. The resin composition obtained in Comparative Example 2 was poor in tracking resistance. The resin composition obtained in Comparative Example 3 was poor in mechanical strength and dimensional stability. The resin composition obtained in Comparative Example 4 was poor in tracking resistance. The resin composition obtained in Comparative Example 5 was poor in flame retardancy. The resin composition obtained in Comparative Example 6 was poor in mechanical strength and flame retardancy. The resin composition obtained in Comparative Example 7 was poor in tracking resistance. The resin composition obtained in Comparative Example 8 was poor in mechanical strength, toughness, and melt fluidity. The resin composition obtained in Comparative Example 9 was poor in mechanical strength, toughness, and dimensional stability. The resin composition obtained in Comparative Example 10 was poor in toughness and melt fluidity. [Industrial Applicability]

[0070] The present invention provides a polyarylene sulfide composition that has excellent electrical properties such as tracking resistance, as well as excellent mechanical strength, toughness, and flame retardancy, and that is also excellent in dimensional stability and melt flowability. The polyarylene sulfide composition is useful for electrical component applications such as electric / electronic components and automotive electrical components, and as electrical component cases, particularly for electrical components used under high voltages such as cases for insulated gate bipolar transistor modules, which are large-capacity power modules, and is therefore of extremely high industrial value.

Claims

1. A polyarylene sulfide composition characterized by comprising, per 100 parts by weight of polyarylene sulfide (A), at least 3 to 45 parts by weight of an ethylene-vinyl alcohol copolymer (B), which is an ethylene-fatty acid vinyl ester-vinyl alcohol copolymer and / or an ethylene-vinyl alcohol copolymer, having a melt flow rate of 3 to 1050 g / 10 min, as measured using a high-temperature flow tester equipped with a die having a diameter of 1 mm and a length of 2 mm under conditions of a measurement temperature of 190°C and a load of 2.16 kg; 0.5 to 30 parts by weight of a polyolefin elastomer (C); 50 to 200 parts by weight of magnesium hydroxide (D); and 50 to 200 parts by weight of a fibrous filler (E) having a flat cross section.

2. 2. The polyarylene sulfide composition according to claim 1, wherein the ethylene-vinyl alcohol copolymer (B) is represented by the following general formula (1): 【Chemistry 1】 (wherein x = 0.25 to 0.90, y = 0 to 0.08, z = 0.02 to 0.75, x + y + z = 1, and R is a hydrocarbon group having 1 to 10 carbon atoms.)

3. The polyarylene sulfide composition according to claim 2, characterized in that the ethylene-vinyl alcohol copolymer (B) is one in which x = 0.69 to 0.90, y = 0 to 0.08, and z = 0.05 to 0.40 in the general formula (1).

4. 2. The polyarylene sulfide composition according to claim 1, wherein the ethylene-vinyl alcohol copolymer (B) is an ethylene-vinyl acetate-vinyl alcohol copolymer.

5. 2. The polyarylene sulfide composition according to claim 1, wherein the polyolefin elastomer (C) is at least one modified ethylene polymer selected from the group consisting of ethylene-α,β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymers, ethylene-α,β-unsaturated carboxylic acid glycidyl ester copolymers, ethylene-α,β-unsaturated carboxylic acid glycidyl ester-vinyl acetate copolymers, ethylene-α,β-unsaturated carboxylic acid glycidyl ester-α,β-unsaturated carboxylic acid alkyl ester copolymers, and maleic anhydride-grafted modified ethylene polymers.

6. The polyarylene sulfide composition according to claim 1, characterized in that the fibrous filler (E) having a flat cross-sectional shape has a ratio of the major axis to the minor axis in the fiber cross section (major axis / minor axis) in the range of 2 to 20.

7. The polyarylene sulfide composition according to claim 1, characterized in that it contains 80 to 150 parts by weight of magnesium hydroxide (D) and 80 to 150 parts by weight of a fibrous filler (E) having a flat cross-sectional shape, relative to 100 parts by weight of the polyarylene sulfide (A).

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